U.S. patent number 10,399,206 [Application Number 15/402,525] was granted by the patent office on 2019-09-03 for polycrystalline diamond compacts, methods of fabricating the same, and methods of using the same.
This patent grant is currently assigned to US SYNTHETIC CORPORATION. The grantee listed for this patent is US SYNTHETIC CORPORATION. Invention is credited to Matthew Kimball Baker, Kenneth E. Bertagnolli, Joshua Adam Hawks, Jason Lott, Daniel Call Mortensen, Trevor Allen Olsen, Lindsay Sue Patton, Jiang Qian, Shawn Casey Scott, Anne-Grethe Slotnaes, Casey Wade Swan.
View All Diagrams
United States Patent |
10,399,206 |
Mortensen , et al. |
September 3, 2019 |
Polycrystalline diamond compacts, methods of fabricating the same,
and methods of using the same
Abstract
PDCs, methods of fabricating the PDCs, and methods of using the
PDCs are disclosed herein. The PDCs include a PCD table bonded to a
substrate. The PCD table includes an upper surface having a
plurality of recessed features formed therein. The plurality of
recessed features are configured to attract at least some cracks
that form in the PCD table. As such, the plurality of recessed
features limit or prevent crack propagation into other portions of
the PCD table and limit a volume of the PCD table that spalls.
Methods of fabricating the PDCs include partially leaching the PCD
table and, after leaching the PCD table, forming the plurality of
recessed features in the upper surface thereof. Method of using the
PDCs include rotating a PDC that has spalled relative to a rotary
drill bit such that a portion of the upper surface of the PDC that
has not spalled forms a cutting surface thereof.
Inventors: |
Mortensen; Daniel Call (Eagle
Mountain, UT), Patton; Lindsay Sue (Provo, UT), Olsen;
Trevor Allen (Spanish Fork, UT), Swan; Casey Wade
(Spanish Fork, UT), Scott; Shawn Casey (Payson, UT),
Baker; Matthew Kimball (Provo, UT), Slotnaes;
Anne-Grethe (South Jordan, UT), Bertagnolli; Kenneth E.
(Riverton, UT), Qian; Jiang (Cedar Hills, UT), Lott;
Jason (Payson, UT), Hawks; Joshua Adam (Saratoga
Springs, UT) |
Applicant: |
Name |
City |
State |
Country |
Type |
US SYNTHETIC CORPORATION |
Orem |
UT |
US |
|
|
Assignee: |
US SYNTHETIC CORPORATION (Orem,
UT)
|
Family
ID: |
67770028 |
Appl.
No.: |
15/402,525 |
Filed: |
January 10, 2017 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
62279271 |
Jan 15, 2016 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B24D
3/007 (20130101); E21B 10/633 (20130101); E21B
10/5673 (20130101); B24D 3/10 (20130101); E21B
10/55 (20130101); E21B 10/62 (20130101) |
Current International
Class: |
E21B
10/62 (20060101); E21B 10/633 (20060101); B24D
3/00 (20060101); B24D 3/10 (20060101); E21B
10/567 (20060101); E21B 10/55 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
US. Appl. No. 12/830,878, filed Jul. 6, 2010, Wiggins et al. cited
by applicant .
U.S. Appl. No. 12/961,787, filed Dec. 7, 2010, Mukhopadhyay et al.
cited by applicant .
U.S. Appl. No. 13/324,237, filed Dec. 13, 2011, Kidd et al. cited
by applicant .
U.S. Appl. No. 13/486,578, filed Jun. 1, 2012, Bertagnolli et al.
cited by applicant .
U.S. Appl. No. 13/734,354, filed Jan. 4, 2013, Linford et al. cited
by applicant .
U.S. Appl. No. 13/790,046, filed Mar. 8, 2013, Cox. cited by
applicant .
U.S. Appl. No. 61/948,970, filed Mar. 6, 2014, Knuteson et al.
cited by applicant .
U.S. Appl. No. 14/273,360, filed May 8, 2014, Burton et al. cited
by applicant .
U.S. Appl. No. 14/275,574, filed May 12, 2014, Burton et al. cited
by applicant .
U.S. Appl. No. 62/002,001, filed May 22, 2014, Knuteson et al.
cited by applicant .
U.S. Appl. No. 14/627,966, filed Feb. 20, 2015, Linford et al.
cited by applicant .
U.S. Appl. No. 14/811,699, filed Jul. 28, 2015, Myers et al. cited
by applicant .
U.S. Appl. No. 62/232,732, filed Sep. 25, 2015, Weaver et al. cited
by applicant .
U.S. Appl. No. 62/279,271, filed Jan. 15, 2016, Mortensen et al.
cited by applicant .
U.S. Appl. No. 29/559,713, filed Mar. 30, 2016, Mortensen et al.
cited by applicant .
U.S. Appl. No. 61/891,525, filed Oct. 16, 2013, Miess. cited by
applicant .
U.S. Appl. No. 14/515,768, filed Oct. 16, 2014, Mortensen et al.
cited by applicant .
U.S. Appl. No. 14/515,768, Jan. 29, 2016, Restriction Requirement.
cited by applicant .
U.S. Appl. No. 14/515,768, May 31, 2016, Office Action. cited by
applicant .
U.S. Appl. No. 14/515,768, Nov. 14, 2016, Office Action. cited by
applicant .
U.S. Appl. No. 16/008,935, Jun. 14, 2018, Miess. cited by applicant
.
U.S. Appl. No. 14/515,768, Jul. 13, 2017, Office Action. cited by
applicant .
U.S. Appl. No. 14/515,768, Nov. 24, 2017, Notice of Allowance.
cited by applicant .
U.S. Appl. No. 14/515,768, Mar. 15, 2018, Notice of Allowance.
cited by applicant .
U.S. Appl. No. 29/559,713, Jan. 29, 2018, Restriction Requirement.
cited by applicant .
U.S. Appl. No. 14/515,768, Feb. 3, 2017, Advisory Action. cited by
applicant .
U.S. Appl. No. 14/515,768, Mar. 6, 2017, Non-Final Office Action.
cited by applicant .
U.S. Appl. No. 14/515,768, Jun. 27, 2018, Issue Notification. cited
by applicant .
U.S. Appl. No. 29/559,713, Jul. 19, 2018, Notice of Allowance.
cited by applicant .
U.S. Appl. No. 29/559,713, Nov. 14, 2018, Issue Notification. cited
by applicant.
|
Primary Examiner: Hutchins; Cathleen R
Attorney, Agent or Firm: Dorsey & Whitney LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION(S)
This application claims priority to U.S. Provisional Application
No. 62/279,271 filed on 15 Jan. 2016, the disclosure of which is
incorporated herein, in its entirety, by this reference.
Claims
What is claimed is:
1. A polycrystalline diamond compact, comprising: a substrate; and
a polycrystalline diamond table bonded to the substrate, the
polycrystalline diamond table including an interfacial surface
bonded to the substrate, an upper surface spaced from the
interfacial surface, and at least one lateral surface extending
between the upper surface and the interfacial surface, the
polycrystalline diamond table including a plurality of diamond
grains bonded together defining a plurality of interstitial
regions, the polycrystalline diamond table including: an unleached
region bonded to the interfacial surface, the unleached region
including at least one interstitial constituent disposed in at
least a portion of the plurality of interstitial regions thereof; a
leached region extending inwardly from the upper surface and at
least a portion of the at least one lateral surface, the leached
region being at least partially depleted of the at least one
interstitial constituent; a plurality of recessed features
extending from the upper surface through a portion of the
polycrystalline diamond table, wherein a majority of the plurality
of recessed features do not extend into the unleached region;
wherein the leached region exhibits a first leach depth measured
from the upper surface and a second leach depth measured from a
base of each of the plurality of recessed features that is less
than the first leach depth; and wherein at least some of the
plurality of recessed features exhibit an average maximum width and
an average maximum depth, the average maximum depth is greater than
or equal to the average maximum width.
2. The polycrystalline diamond compact of claim 1, wherein the
second leach depth is about 1% to about 75% less than the first
leach depth.
3. The polycrystalline diamond compact of claim 1, wherein a depth
of at least some of the plurality of recessed features exhibit a
depth measured from the upper surface to a base thereof that is
different from at least some other of the plurality of recessed
features.
4. The polycrystalline diamond compact of claim 1, wherein the
first leach depth is about 200 .mu.m to about 900 .mu.m.
5. The polycrystalline diamond compact of claim 1, wherein a depth
of at least some of the plurality of recessed features exhibits a
depth measured from the upper surface to the base thereof that is
about 50 .mu.m to about 500 .mu.m.
6. The polycrystalline diamond compact of claim 1, further
comprising a plurality of cells at least partially defined by at
least one of the plurality of recessed features, each of the
plurality of cells exhibits an average surface area that is 5% of a
total surface area of the upper surface or less.
7. The polycrystalline diamond compact of claim 1, wherein the
plurality of recessed features includes at least two immediately
adjacent recessed features, at least a portion of each of the at
least two immediately adjacent recessed features are substantially
parallel to each other and exhibit a distance therebetween that is
about 650 .mu.m or less.
8. The polycrystalline diamond compact of claim 1, wherein the
plurality of recessed features exhibit a generally arcuate
cross-section in side view, a generally triangular cross-section in
side view, or a generally rectangular cross-section in side
view.
9. The polycrystalline diamond compact of claim 1, wherein at least
some of the plurality of recessed features extend generally
radially.
10. The polycrystalline diamond compact of claim 1, wherein at
least some of the plurality of recessed features extend along a
spiral path.
11. The polycrystalline diamond compact of claim 1, wherein at
least some of the plurality of recessed features generally forms at
least one of a hypocycloid, hypotrochoid, or a generally
commonly-centered shape.
12. The polycrystalline diamond compact of claim 1, wherein the
plurality of recessed features form a triangular grid-like pattern,
a rectangular grid-like pattern, or a hexagonal grid-like
pattern.
13. The polycrystalline diamond compact of claim 1, wherein the
leached region exhibits an L.sub.1* value that is about 50 .mu.m to
about 1200 .mu.m, the L.sub.1* value is a distance between an
initial wear front and an interface between the leached region and
the unleached region, wherein the initial wear front is a plane
extending at about 20.degree. angle relative to the at least one
lateral surface, wherein the distance is a shortest distance from
the initial wear front to the interface between the leached region
and the unleached region measured substantially perpendicularly
relative to the initial wear front.
14. A rotary drill bit, comprising: a bit body configured to engage
a subterranean formation; and a plurality of polycrystalline
diamond cutting elements affixed to the bit body, at least one of
the polycrystalline diamond cutting elements including: a
substrate; and a polycrystalline diamond table bonded to the
substrate, the polycrystalline diamond table including an
interfacial surface bonded to the substrate, an upper surface
spaced from the interfacial surface, and at least one lateral
surface extending between the upper surface and the interfacial
surface, the polycrystalline diamond table including a plurality of
diamond grains bonded together defining a plurality of interstitial
regions, the polycrystalline diamond table including: a plurality
of recessed features extending from the upper surface through a
portion of the polycrystalline diamond table; an unleached region
bonded to the interfacial surface, the unleached region including
at least one interstitial constituent disposed in at least a
portion of the plurality of interstitial regions thereof; a leached
region extending inwardly from the upper surface and at least a
portion of the at least one lateral surface, the leached region
being at least partially depleted of the at least one interstitial
constituent, wherein the leached region exhibits a first leach
depth measured from the upper surface and a second leach depth
measured from a base of each of the plurality of recessed features
that is less than the first leach depth, and wherein a majority of
the plurality of recessed features do not extend into the unleached
region; and wherein at least some of the plurality of recessed
features exhibit an average maximum width and an average maximum
depth, the average maximum depth is greater than or equal to the
average maximum width.
15. A polycrystalline diamond compact, comprising: a substrate; and
a polycrystalline diamond table bonded to the substrate, the
polycrystalline diamond table including an interfacial surface
bonded to the substrate, an upper surface spaced from the
interfacial surface, and at least one lateral surface extending
between the upper surface and the interfacial surface, the
polycrystalline diamond table including a plurality of diamond
grains bonded together defining a plurality of interstitial
regions, the polycrystalline diamond table including: an unleached
region bonded to the interfacial surface, the unleached region
including at least one interstitial constituent disposed in at
least a portion of the plurality of interstitial regions thereof; a
leached region extending inwardly from the upper surface and at
least a portion of the at least one lateral surface, the leached
region being at least partially depleted of the at least one
interstitial constituent; a plurality of recessed features
extending from the upper surface through a portion of the
polycrystalline diamond table, the plurality of recessed features
forming a plurality of cells; wherein an initial spallation of the
polycrystalline diamond table in response to a milling spallation
test is about 10% or less of the area of the upper surface of the
polycrystalline diamond table; and wherein the leached region
exhibits a first leach depth measured from the upper surface and a
second leach depth measured from a base of each of the plurality of
recessed features that is less than the first leach depth; and
wherein at least some of the plurality of recessed features exhibit
an average maximum width and an average maximum depth, the average
maximum depth is greater than or equal to the average maximum
width.
16. A polycrystalline diamond compact, comprising: a substrate; and
a polycrystalline diamond table bonded to the substrate, the
polycrystalline diamond table including an interfacial surface
bonded to the substrate, an upper surface spaced from the
interfacial surface, and at least one lateral surface extending
between the upper surface and the interfacial surface, the
polycrystalline diamond table including a plurality of diamond
grains bonded together defining a plurality of interstitial
regions, the polycrystalline diamond table including: a plurality
of recessed features extending from the upper surface through a
portion of the polycrystalline diamond table; wherein the
polycrystalline diamond table exhibits a probability of failure
less than about 0.4 at a distance cut of at least about 325 inches
when tested in a milling spallation test; an unleached region
bonded to the interfacial surface, the unleached region including
at least one interstitial constituent disposed in at least a
portion of the plurality of interstitial regions thereof; a leached
region extending inwardly from the upper surface and at least a
portion of the at least one lateral surface, the leached region
being at least partially depleted of the at least one interstitial
constituent; wherein the leached region exhibits a first leach
depth measured from the upper surface and a second leach depth
measured from a base of each of the plurality of recessed features
that is less than the first leach depth; and wherein at least some
of the plurality of recessed features exhibit an average maximum
width and an average maximum depth, the average maximum depth is
greater than or equal to the average maximum width.
Description
BACKGROUND
Wear-resistant, polycrystalline diamond compacts ("PDCs") are
utilized in a variety of mechanical applications. For example, PDCs
are used in drilling tools (e.g., cutting elements, gage trimmers,
etc.), machining equipment, bearing apparatuses, wire-drawing
machinery, and in other mechanical apparatuses.
PDCs have found particular utility as superabrasive cutting
elements in rotary drill bits, such as roller-cone drill bits and
fixed-cutter drill bits. A PDC cutting element typically includes a
superabrasive diamond layer commonly known as a diamond table. The
diamond table is formed and bonded to a substrate using a
high-pressure/high-temperature ("HPHT") process that sinters
diamond particles under diamond-stable conditions. The PDC cutting
element may also be brazed directly into a preformed pocket,
socket, or other receptacle formed in a bit body. The substrate may
optionally be brazed or otherwise joined to an attachment member,
such as a cylindrical backing. A rotary drill bit typically
includes a number of PDC cutting elements affixed to the bit body.
It is also known that a stud carrying the PDC may be used as a PDC
cutting element when attached to a bit body of a rotary drill bit
by press-fitting, brazing, or otherwise securing the stud into a
receptacle formed in the bit body.
Conventional PDCs are normally fabricated by placing a cemented
carbide substrate into a container with a volume of diamond
particles positioned on a surface of the cemented carbide
substrate. A number of such containers may be loaded into an HPHT
press. The substrate(s) and volume of diamond particles are then
processed under HPHT conditions in the presence of a catalyst
material that causes the diamond particles to bond to one another
to form a matrix of bonded diamond grains defining a
polycrystalline diamond ("PCD") table. The catalyst material is
often a metal-solvent catalyst (e.g., cobalt, nickel, iron, or
alloys thereof) that is used for promoting intergrowth of the
diamond particles.
In a conventional approach, a constituent of the cemented carbide
substrate, such as cobalt from a cobalt-cemented tungsten carbide
substrate, liquefies and sweeps from a region adjacent to the
volume of diamond particles into interstitial regions between the
diamond particles during the HPHT sintering process. The cobalt
acts as a catalyst to promote intergrowth between the diamond
particles, which results in formation of a matrix of bonded diamond
grains having diamond-to-diamond bonding there between, with
interstitial regions between the bonded diamond grains being
occupied by the solvent catalyst.
The presence of the metal-solvent catalyst in the PCD table is
believed to reduce the thermal stability of the PCD table at
elevated temperatures. For example, the difference in thermal
expansion coefficient between the diamond grains and the
metal-solvent catalyst is believed to lead to chipping or cracking
of the PCD table during drilling or cutting operations, which can
degrade the mechanical properties of the PCD table or cause
failure. Additionally, some of the diamond grains can undergo a
chemical breakdown or back-conversion to graphite via interaction
with the solvent catalyst. At elevated high temperatures, portions
of diamond grains may transform to carbon monoxide, carbon dioxide,
graphite, or combinations thereof, thereby degrading the mechanical
properties of the PDC.
One conventional approach for improving the thermal stability of a
PDC is to at least partially remove the metal-solvent catalyst from
the PCD table of the PDC by acid leaching. Another approach
involves infiltrating and bonding an at least partially leached PCD
table to a cemented carbide substrate with a metallic infiltrant,
and acid leaching to at least partially remove the metallic
infiltrant.
Despite the availability of a number of different PDCs,
manufacturers and users of PDCs continue to seek PDCs that exhibit
improved toughness, wear resistance, and thermal stability.
SUMMARY
PDCs, methods of fabricating the PDCs, and methods of using the
PDCs are disclosed herein. The PDCs include a PCD table bonded to a
substrate. The PCD table includes an upper surface having a
plurality of recessed features formed therein. The plurality of
recessed features function as stress concentrations that are
configured to attract at least some cracks that form in the PCD
table. As such, the plurality of recessed features limit or prevent
propagation of the cracks into other portions of the PCD table and
limit a volume of the PCD table that spalls during cutting
operations. Methods of fabricating the PDCs include partially
leaching the PCD table and, after leaching the PCD table, forming
the plurality of recessed features in the upper surface thereof.
Method of using the PDCs include rotating a PDC that has spalled
relative to a rotary drill bit such that a portion of the upper
surface of the PDC that has not spalled forms a cutting surface
thereof. The disclosed PDCs may be used in a variety of
applications, such as rotary drill bits, machining equipment, and
other articles and apparatuses.
In an embodiment, a PDC is disclosed. The PDC includes a substrate.
The PDC also includes a PCD table bonded to the substrate. The PCD
table includes an interfacial surface bonded to the substrate, an
upper surface spaced from the interfacial surface, and at least one
lateral surface extending between the upper surface and the
interfacial surface. The PCD table also includes a plurality of
diamond grains bonded together defining a plurality of interstitial
regions. The PCD table further includes an unleached region bonded
to the interfacial surface. The unleached region includes at least
one interstitial constituent disposed in at least a portion of the
plurality of interstitial regions thereof. The PCD table also
includes a leached region extending inwardly from the upper surface
and at least a portion of the at least one lateral surface. The
leached region is at least partially depleted of the at least one
interstitial constituent. The PCD table additionally includes a
plurality of recessed features extending from the upper surface
through a portion of the polycrystalline diamond table. A majority
of the plurality of recessed features do not extend into the
unleached region.
In an embodiment, a method of fabricating a PDC is disclosed. The
method includes leaching at least a portion of at least one
interstitial constituent from a polycrystalline diamond table to a
leach depth measured inwardly from an upper surface and at least
one lateral surface of the polycrystalline diamond table to form a
leached region. The method also includes, after leaching the
polycrystalline diamond table, forming a plurality of recessed
features that extend from the upper surface of the polycrystalline
diamond table to a depth less than the leach depth of the leached
region. Forming the plurality of recessed features forms a
plurality of cells on the upper surface that are at least partially
defined by the plurality of recessed features.
In an embodiment, a method of using a PDC is disclosed. The method
includes decoupling at least one PDC from a drill bit body. The at
least one PDC includes a PCD table bonded to a substrate. A portion
of the PCD table includes a spalled region. The PCD table includes
an interfacial surface bonded to the substrate, an upper surface
spaced from the interfacial surface, and at least one lateral
surface extending between the upper surface and the interfacial
surface. The PCD table also includes a plurality of diamond grains
bonded together defining a plurality of interstitial regions. The
PCD table further includes a plurality of recessed features
extending from the upper surface of the polycrystalline diamond
table through a portion of the polycrystalline diamond table. At
least one of the plurality of recessed features partially defines
the spall region. Additionally, the PCD table includes an unleached
region bonded to the interfacial surface. The unleached region
includes an interstitial constituent disposed in at least a portion
of the plurality of interstitial regions thereof. Finally, the PCD
table includes a leached region extending inwardly from the upper
surface and at least a portion of at least one lateral surface. The
leached region is at least partially depleted of at least one
interstitial constituent. A majority of the plurality of recessed
features do not extend into the unleached region. The method also
includes rotating the at least one PDC relative to the drill bit
body to position a portion of the PCD table that does not include
the spalled region in a cutting position. The method further
includes coupling the at least one PDC to the drill bit body with
the PCD table positioned in the cutting position.
In an embodiment, a PDC includes a substrate and a PCD table bonded
to the substrate. The PCD table includes an interfacial surface
bonded to the substrate, an upper surface spaced from the
interfacial surface, and at least one lateral surface extending
between the upper surface and the interfacial surface. The PCD
table further includes a plurality of diamond grains bonded
together defining a plurality of interstitial regions. The PCD
table also includes an unleached region bonded to the interfacial
surface, with the unleached region including at least one
interstitial constituent disposed in at least a portion of the
plurality of interstitial regions thereof; a leached region
extending inwardly from the upper surface and at least a portion of
the at least one lateral surface, with the leached region being at
least partially depleted of the at least one interstitial
constituent; and a plurality of recessed features extending from
the upper surface through a portion of the PCD table, with the
plurality of recessed features forming a plurality of cells. An
initial spallation of the PCD table in response to a milling
spallation test is about 10% or less of the area of the upper
surface of the PCD table.
In an embodiment, a PDC includes a substrate and a PCD table bonded
to the substrate. The PCD table includes an interfacial surface
bonded to the substrate, an upper surface spaced from the
interfacial surface, and at least one lateral surface extending
between the upper surface and the interfacial surface. The PCD
table further includes a plurality of diamond grains bonded
together defining a plurality of interstitial regions. The PCD
table also includes a plurality of recessed features extending from
the upper surface through a portion of the PCD table; an unleached
region bonded to the interfacial surface, with the unleached region
including at least one interstitial constituent disposed in at
least a portion of the plurality of interstitial regions thereof;
and a leached region extending inwardly from the upper surface and
at least a portion of the at least one lateral surface, with the
leached region being at least partially depleted of the at least
one interstitial constituent. The PCD table exhibits a probability
of failure less than about 0.4 at a distance cut of at least about
325 inches when tested in a milling spallation test.
Other embodiments include applications utilizing the disclosed PDCs
in various articles and apparatuses, such as rotary drill bits,
bearing apparatuses, wire-drawing dies, machining equipment, and
other articles and apparatuses.
Features from any of the disclosed embodiments may be used in
combination with one another, without limitation. In addition,
other features and advantages of the present disclosure will become
apparent to those of ordinary skill in the art through
consideration of the following detailed description and the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings illustrate several embodiments of the present
disclosure, wherein identical reference numerals refer to identical
or similar elements or features in different views or embodiments
shown in the drawings.
FIG. 1A is an isometric view of a PDC, according to an
embodiment.
FIG. 1B is a side, cross-sectional view of the PDC shown in FIG. 1A
taken along plane 1B-1B thereof.
FIG. 2 is a side, cross-sectional view of a PDC that includes a
partially leached PCD table, according to an embodiment.
FIG. 3 is a schematic illustration of an embodiment of a method for
fabricating a PDC that may be used in any of the embodiments
disclosed herein, according to an embodiment.
FIGS. 4A-4C are partial, side, cross-sectional views of PCD tables
that include at least one recessed feature formed therein that each
exhibit different cross-sectional geometries, according to
different embodiments.
FIGS. 5-10E are top plan views of PCD tables that exhibit different
patterns of a plurality of recessed features formed in an upper
surface thereof, according to different embodiments.
FIG. 11 is a photograph of a conventional PDC after the
conventional PDC spalled.
FIGS. 12A-12G are photographs of different working examples of PDCs
according to embodiments of the present disclosure, which include a
plurality of recessed features formed thereon, after the different
PDCs have spalled.
FIG. 13 is a graph showing probability of failure of comparative
example 1 and working examples 2, 7, 8, and 9 versus distance each
PDC cut prior to failure.
FIG. 14A is an isometric view of an embodiment of a rotary drill
bit that may employ one or more of the disclosed PDC
embodiments.
FIG. 14B is a top plan view of the rotary drill bit shown in FIG.
14A.
DETAILED DESCRIPTION
PDCs, methods of fabricating the PDCs, and methods of using the
PDCs are disclosed herein. The PDCs include a PCD table bonded to a
substrate. The PCD table includes an upper surface having a
plurality of recessed features formed therein. The plurality of
recessed features function as stress concentrations that are
configured to attract at least some cracks that form in the PCD
table. As such, the plurality of recessed features limit or prevent
propagation of the cracks into other portions of the PCD table and
limit a volume or area of the PCD table that spalls during cutting
operations. Methods of fabricating the PDCs include partially
leaching the PCD table and, after leaching the PCD table, forming
the plurality of recessed features in the upper surface thereof.
Method of using the PDCs include rotating a PDC that has spalled
relative to a rotary drill bit such that a portion of the upper
surface of the PDC that has not spalled forms a cutting surface
thereof. The disclosed PDCs may be used in a variety of
applications, such as rotary drill bits, machining equipment, and
other articles and apparatuses.
FIG. 1A is an isometric view of a PDC 100, according to an
embodiment. The PDC 100 includes a PCD table 102 bonded to a
substrate 104. The PCD table 102 includes an upper surface 106 that
forms at least part of a working surface of the PDC 100. The upper
surface 106 includes a plurality of recessed features 108 (e.g.,
grooves) formed therein. In an embodiment, during cutting
operations using the PDC 100, cracks may form in the PCD table 102.
The plurality of recessed features 108 function as stress
concentrations that are configured to attract cracks thereto,
thereby limiting crack propagation into the PCD table 102 during
cutting operations. As such, the plurality of recessed features 108
may limit spalling to a limited region of the PCD table 102
("spalled region"). Additionally, the plurality of recessed
features 108 limit crack propagation from the spalled region to
other regions of the PCD table 102. In an embodiment, the plurality
of recessed features 108 may be sized and configured to limit a
spalled region to 10% or less, 5% of less, 4% or less, or 3% or
less, about 3% to about 10%, about 5% to about 8%, or about 4% to
about 7% of a total surface area of the upper surface 106. As such,
the plurality of recessed features 108 may help maintain one or
more of a structural integrity, a strength, or a toughness of the
PCD table 102.
In some embodiments, a probability of failure as determined in a
milling spallation test, which is described in comparative example
1 below, may be less than about 0.1 at a distance cut of about 315
inches or greater (e.g., about 315 inches to about 325 inches,
about 325 inches to about 350, about 350 inches or greater), may be
less than about 0.3 to about 0.4 at a distance cut of about 325
inches or greater (e.g., about 325 inches to about 350 inches,
about 350 inches to about 375 inches, at least about 350 inches, at
least about 375 inches, about 375 inches to about 400 inches, or
greater than 400 inches), may be less than about 0.75 at a distance
cut of about 340 inches or greater (e.g., about 350 inches to about
375 inches, about 375 inches to about 400 inches, about 400 inches
to about 425 inches, about 425 inches or greater).
The substrate 104 may include a cemented carbide material. For
example, the substrate 104 may include tungsten carbide, titanium
carbide, chromium carbide, niobium carbide, tantalum carbide,
vanadium carbide, or combinations thereof that may be cemented with
iron, nickel, cobalt, combinations thereof, or alloys thereof. For
example, the substrate 104 may comprise a cobalt-cemented tungsten
carbide. In some embodiments, the substrate 104 may be omitted
(e.g., a free-standing PCD table).
The PCD table 102 includes an interfacial surface 110 that is
spaced from the upper surface 106 and bonded to the substrate 104.
The interfacial surface 110 may be substantially planar (FIG. 1B),
exhibit a concave or convex curvature, or have one or more recesses
and/or protrusions formed therein. The substrate 104 may include a
surface that substantially corresponds to the interfacial surface
110. The PCD table 102 may also include at least one lateral
surface 112 that extends from the interfacial surface 110 to the
upper surface 106. In some embodiments, the PCD table 102 may
include an optional chamfer 114 extending between the at least one
lateral surface 112 and the upper surface 106. In other
embodiments, the PCD table 102 may include a rounded edge, multiple
chamfers (e.g., double chamfer), or any other suitable edge
geometry.
In the illustrated embodiments shown in FIGS. 1A-1B, the PDCs are
cylindrical. However, in other embodiments, the PDCs disclosed
herein may exhibit other suitable configurations (e.g., triangular,
rectangular, elliptical, or other suitable configuration) that may
exhibit one or more peripheral surfaces or sides.
The PCD table 102 includes a plurality of directly bonded together
diamond grains that exhibit diamond-to-diamond bonding therebetween
(e.g., sp.sup.3 bonding). The plurality of directly bonded together
diamond grains define a plurality of interstitial regions
therebetween. The PCD table 102 may include at least one
interstitial constituent that at least partially occupies at least
some of the interstitial regions of the PCD table 102. The at least
one interstitial constituent may include at least one of a
metal-solvent catalyst (e.g., cobalt, iron, nickel, combinations
thereof, or alloys thereof), at least one constituent from the
substrate (e.g., tungsten and/or tungsten carbide), a nonmetallic
catalyst (e.g., one or more alkali metal carbonates, one or more
alkaline metal carbonates, one or more alkaline earth metal
hydroxides, or combinations thereof), or another suitable
interstitial constituent.
The at least one interstitial constituent may be at least partially
leached from the PCD table 102. For example, FIG. 1B is a side,
cross-sectional view of the PDC 100 shown in FIG. 1A taken along
plane 1B-1B thereof. The PCD table 102 includes an unleached region
116 that is bonded to the substrate 104. The unleached region 116
may extend from the interfacial surface 110 towards the upper
surface 106. The unleached region 116 is a portion of the PCD table
102 that is not leached and includes the at least one interstitial
constituent therein that at least partially occupies (e.g., at
least substantially occupies) at least some of the interstitial
regions thereof.
The PCD table 102 also includes a leached region 118 that extends
inwardly from the upper surface 106, at least a portion of the at
least one lateral surface 112, and the optional chamfer 114. For
example, an interface 119 is located between the leached region 118
and the unleached region 116. The leached region 118 includes at
least some of the at least one interstitial constituent removed
from the interstitial regions thereof (e.g., the leached region 118
exhibits a lower concentration of the at least one interstitial
constituent than the unleached region 116). For example, a residual
amount of the at least one interstitial constituent may still
remain in the interstitial regions of the leached region 118 after
leaching. The residual amount of the at least one interstitial
constituent in the interstitial regions of the leached region 118
may be about 0.5% to about 2% by weight (e.g., about 0.8% to about
1.2% by weight), or less than about 0.5% by weight (e.g.,
substantially completely removed from the interstitial regions of
the leached region 118). In an embodiment, the leached region 118
may extend inwardly along at least about 50% of a length of the at
least one lateral surface 112 (i.e., from the interfacial surface
110 to a bottommost edge 123 of the chamfer 114), such as along at
least about 75% of the at least one lateral surface 112, along at
least about 80% of the at least one lateral surface 112, or along
at least about 90% of the at least one lateral surface 112. As will
be discussed later, increasing the percentage of the at least one
lateral surface 112 that is leached may allow the L.sub.1* value to
increase (FIG. 2).
The leached region 118 may exhibit a first leach depth D.sub.1
measured substantially perpendicularly inwardly from the upper
surface 106 to the interface 119 between the leached region 118 and
the unleached region 116. The first leach depth D.sub.1 may be
about 200 .mu.m to about 900 .mu.m. For example, the first leach
depth D.sub.1 may be about 200 .mu.m to about 400 .mu.m, about 400
.mu.m to about 500 .mu.m, about 500 .mu.m to about 800 .mu.m, about
800 .mu.m to about 900 .mu.m, less than 200 .mu.m, or greater than
900 .mu.m. In an embodiment, the first leach depth D.sub.1 may be
substantially uniform along a selected length of the upper surface
106. In an embodiment, the first leach depth D.sub.1 may vary long
a selected length of the upper surface 106. For example, as will be
discussed in more detail below, the first leach depth D.sub.1 may
be greater at and/or near an edge of the upper surface 106 (e.g.,
where the upper surface 106 meets the at least one lateral surface
112, the chamfer 114, etc.) than a location spaced from the edge of
the upper surface 106. The leached region 118 may also exhibit
leach depths measured substantially perpendicularly inwardly from
the chamfer 114 and the at least one lateral surface 112,
respectively. In an embodiment, the leach depth measured
substantially perpendicularly inwardly from at least a portion of
the chamfer 114 and at least a portion of the at least one lateral
surface 112 may be substantially the same as or similar to the
first leach depth D.sub.1. In another embodiment, the leached depth
measured substantially perpendicularly inwardly from at least a
portion of the chamfer 114 and/or a portion of the at least one
lateral surface 112 may be different than the first leach depth
D.sub.1. For example, the leach depth measured substantially
perpendicularly inwardly from a portion of the at least one lateral
surface 112 may be greater than the first leach depth D.sub.1.
Additional examples of leach profiles that the leached region 118
may exhibit are disclosed in U.S. Pat. No. 8,596,387, the
disclosure of which in incorporated herein, in its entirety, by
this reference.
The leach profile (e.g., the leach depth measured inwardly from the
upper surface 106, the at least one lateral surface 112, and/or the
optional chamfer 114) may be used to predict when the PDC 100
spalls. FIG. 1B illustrates a predicted initial wear front 120
before the PDC 100 has been used and experienced wear. The
predicted initial wear front 120, in an embodiment, may be
represented as an idealized, hypothetical plane that extends at an
angle .theta. relative to the at least one lateral surface 112. The
angle .theta. may be about 10.degree. to about 30.degree., such as
about 20.degree.. The predicted initial wear front 120 also
exhibits a single point of tangency with a portion of the PCD table
102. For example, in the illustrated embodiment, the predicted
initial wear front 120 may intersect (e.g., at a single point) with
a bottommost edge 123 of the chamfer 114. In another example, the
predicted initial wear front 120 may intersect (e.g., at a single
point) an outer edge of the upper surface 106, one or more portions
of the upper surface 106 (e.g., the upper surface 106 exhibits a
convex curvature), or any other portion or portions of the PDC
100.
During operation, portions of the PCD table 102 may generally wear
away along an expected wear front 122. In an embodiment, the
expected wear front 122 may be assumed to be generally parallel to
the predicted initial wear front 120. In such an embodiment, the
expected wear front 122 may be a plane that extends at the angle
.theta. relative to the at least one lateral surface 112. The
inventors currently believe that at least of one or more
microscopic cracks or other defect forms near the interface 119
between the leached region 118 and the unleached region 116 when
the expected wear front 122 extends through the leached region 118
and contacts the unleached region 116. The inventors currently
believe that the cracks and/or other defect(s) may form a leach
boundary-wear intersection location 124 that increases a likelihood
that the PCD table 102 spalls.
The PCD table 102 may be expected to spall in response to the
expected wear front 122 intersecting with the interface 119 between
the unleached region 116 and the leached region 118 (e.g., the
first location where the leach boundary-wear intersection location
124 may form). The shortest distance measured substantially
perpendicularly from the predicted initial wear front 120 (e.g.,
having an angle .theta. of about 20.degree.) and the interface 119
is referred to as the L.sub.1* value (e.g., the distance measured
substantially perpendicularly between the predicted initial wear
front 120 and the subsequent expected wear front 122 intersecting
with the interface 119). In other words, the L.sub.1* value is the
expected amount of wear into the PCD table 102 before the PCD table
102 becomes more susceptible to spallation. In the illustrated
embodiment, the L.sub.1* value is measured between the predicted
initial wear front 120 and a portion of the interface 119 that is
spaced from the at least one lateral surface 112.
The leach profile of the leached region 118 may be configured to
maximize the L.sub.1* value. For example, in the illustrated
embodiment, increasing one or more of the first leach depth
D.sub.1, the leach depth measured inwardly from the chamfer 114, or
the leach depth measured inwardly from the at least one lateral
surface may increase the L.sub.1* value. In particular, increasing
the leach depth measured inwardly from of the at least one lateral
surface may increase the L.sub.1* value more than increasing the
first leach depth D.sub.1. Additionally, forming the chamfer 114 in
the PCD table 102 prior leaching the PCD table 102 may also
increase the L.sub.1* value. In an embodiment, the L.sub.1* value
may be about 50 .mu.m to about 1200 .mu.m. For example, the
L.sub.1* value may be about 100 .mu.m to about 600 .mu.m, about 100
.mu.m to about 250 .mu.m, about 250 .mu.m to about 500 .mu.m, 500
.mu.m to about 750 .mu.m, or about 750 .mu.m to about 1000 .mu.m.
In an embodiment, the L.sub.1* value may be less than 50 .mu.m or
greater than 1200 .mu.m.
As previously discussed, the PCD table 102 includes the plurality
of recessed features 108 formed in the upper surface 106. At least
a portion of the plurality of recessed features 108 may also be
formed in the at least one lateral surface 112 and/or the chamfer
114. The plurality of recessed features 108 are configured to limit
crack propagation and/or spallation in the PCD table 102. In
particular, a crack in the PCD table 102 (e.g., formed at the leach
boundary-wear intersection location 124) may be attracted to the
nearest recessed feature 108 because the nearest recessed feature
108 serves as a stress concentration and a path of least resistance
for crack propagation thereto. As such, the plurality of recessed
features 108 may limit crack propagation into other regions of the
PCD table 102, thereby maintaining a strength and/or a toughness of
the other regions of the PCD table 102. For example, a crack may
cause a portion of the PCD table 102 to spall. However, since the
crack may be attracted to nearby recessed feature 108, the
plurality of recessed features 108 may limit the amount of the PCD
table 102 that spalls. For instance, at least a portion at least
one of the plurality of recessed features 108 may at least
partially define a spalled region or area formed in the PCD table
102. The spalled region may be less than 10% the total area of the
upper surface 106, such as less than 5%, less than 4%, less than
3%, less than 2%, less than 1%, or less than 5% of a total surface
area of the upper surface 106.
Each of the plurality of recessed features 108 includes a base 126
that partially defines each recessed feature 108. The base 126 is
the portion of each of the plurality of recessed features 108 that
is farthest spaced from the upper surface 106. A depth D.sub.3 of
each of the plurality of recessed features 108 is measured
substantially perpendicularly from the upper surface 106 (e.g., an
imaginary continuation of the upper surface 106 that extends over
the recessed feature 108) to the base 126. In an embodiment, the
depth D.sub.3 of each of the plurality of recessed features 108 may
be about 50 .mu.m to about 500 .mu.m, such as about 50 .mu.m to
about 150 .mu.m, 100 .mu.m to about 250 .mu.m, 200 .mu.m to about
400 .mu.m, or about 300 .mu.m to about 500 .mu.m. In an embodiment,
the depth D.sub.3 of each of the plurality of recessed features 108
may be less than about 50 .mu.m or greater than 500 .mu.m. The
depth D.sub.3 of each of the plurality of recessed features 108 may
be selected based on a width or area of the respective recessed
feature 108, the cross-sectional shape (in side view) of the
respective recessed feature 108, the first leach depth D.sub.1, the
L.sub.1* value, the shortest distance between the leach
boundary-wear intersection location 124 and the respective recessed
feature 108, the application of the PDC 100, etc.
In an embodiment, the plurality of recessed features 108 may
potentially adversely affect the strength and toughness of the PCD
table 102. For example, the strength and/or toughness of the PCD
table 102 may decrease as an average depth of the plurality of
recessed features 108 increases. However, the ability of the
plurality of recessed features 108 to attract cracks thereto may
also increase as the average depth of the plurality of recessed
features 108 increases. For example, a recessed feature 108 that is
positioned proximate to the leach boundary-wear intersection
location 124 or that exhibits a relatively high stress
concentration factor may exhibit a depth that is relatively shallow
(e.g., about 50 .mu.m to about 250 .mu.m). In another embodiment, a
recessed feature 108 that is spaced from leach boundary-wear
intersection location 124 or that exhibits a relatively low stress
concentration factor may exhibit a depth that is relatively deep
(e.g., about 250 .mu.m to about 500 .mu.m, greater than 500
.mu.m).
In an embodiment, at least some of the plurality of recessed
features 108 only extend partially through or within the leached
region 118. As such, the leach depth of the remaining leached
region 118 proximate to the at least some of the plurality of
recessed features 108 may be decreased. For example, the leached
region 118 may exhibit a second leach depth D.sub.2 measured
substantially perpendicularly inwardly from the base 126 of each of
the at least some of the plurality of recessed features 108 to the
interface 119 between the leached region 118 and the unleached
region 116. In an embodiment, the second leach depth D.sub.2 may be
about 1% to about 75% less than the first leach depth D.sub.1. For
example, the second leach depth D.sub.2 may be about 1% less than
to about 5% less than, about 5% less than to about 25% less than,
about 20% less than to about 40% less than, about 25% less than to
about 50% less than, or about 50% less than to about 75% less than
the first leach depth D.sub.1. For example, if D.sub.1 equals about
500 .mu.m, then D.sub.2 may be about 20% less than to about 40%
less than D.sub.1 (i.e., 300 .mu.m to about 400 .mu.m). In another
embodiment, the second leach depth D.sub.2 may be greater than 0%
to about 1% less than the first leach depth D.sub.1, about 75% less
than the first leach depth D.sub.1 to completely through the
leached region 118, or about 75% less than the first leach depth
D.sub.1 to substantially through the PCD table 102. As previously
discussed, the percentage of the second leach depth D.sub.2 to the
first leach depth D.sub.1 may potentially affect the performance of
the PDC 100. For example, the second leach depth D.sub.2 of at
least some of the plurality of recessed features 108 may be
significantly less than the first leach depth D.sub.1 (e.g., about
50% to about 75% less than the first leach depth D.sub.1) when the
recessed features 108 are positioned proximate to the anticipated
leach boundary-wear intersection location 124 and/or exhibits a
relatively high stress concentration factor.
In an embodiment, the first leach depth D.sub.1 may be about 1.33
to about 20 times greater than the depth D.sub.3 of at least some
of the plurality of recessed features 108. For example, the first
leach depth D.sub.1 may be about 1.5 to about 5, about 2 to about
10, about 5 to about 15, about 10 to about 15, or about 15 to about
20 times greater than the depth D.sub.3 of at least some of the
plurality of recessed features 108. In an embodiment, the first
leach depth D.sub.1 may be about 1.0 to about 1.33 times greater or
more than 20 times greater than depth D.sub.3 of at least some of
the plurality of recessed features 108. In an embodiment, the depth
D.sub.3 of at least some of the plurality of recessed features 108
may be greater than the first leach depth D.sub.1. As previously
discussed, the depth D.sub.3 of the plurality of recessed features
108 relative to the first leach depth D.sub.1 may affect to the
performance of the PDC 100. For example, the first leach depth
D.sub.1 may be at least about 4 times greater than the depth
D.sub.3 of at least some of the plurality of recessed features 108
when the recessed features 108 are positioned proximate to the
anticipated leach boundary-wear intersection location 124 and/or
exhibits a relatively high stress concentration factor.
In an embodiment, the depth D.sub.3 of at least some of the
plurality of recessed features 108 may vary with location along the
upper surface 106. For example, the depth of at least some of the
plurality of recessed features 108 may generally increase,
decrease, undulate, or vary from a location on the upper surface
106 (e.g., a center of the upper surface 106) towards an edge of
the upper surface 106. For example, the depth D.sub.3 of at least
some of the plurality of recessed features 108 may be greatest at
and/or near the edge of the upper surface 106. As another example,
the depth D.sub.3 of at least some of the plurality of recessed
features 108 may be smallest at and/or near the edge of the upper
surface 106. In an embodiment, the depth D.sub.3 of at least some
of the plurality of recessed features 108 may be greatest at, near,
and/or inwardly from a location where the expected wear front 122
contacts the unleached portion 116. Varying the depth D.sub.3 of at
least some of the plurality of recessed features 108 may increase
the overall strength and toughness of the PCD table 102 because the
average depth of the plurality of recessed features 108 is less
than the greatest depth of the plurality of recessed features 108.
However, the depth of the plurality of recessed features 108 may be
sufficiently deep at certain locations to limit a spalled region
formed in the PCD table 102.
In an embodiment, the plurality of recessed features 108 may be
formed in only a selected portion of the upper surface 106. Forming
the plurality of recessed features 108 in a selected portion of the
upper surface 106 may increase the strength and toughness the PCD
table 102. For example, the plurality of recessed features 108 may
be formed in a radially outer half of the upper surface 106. The
plurality of recessed features 108 may be formed in the radially
outer half of the upper surface 106 because the leach boundary-wear
intersection location 124 may be more likely to occur in the
radially outer half of the PCD table 102. In an embodiment, the
plurality of recessed features 108 may be formed over the entire
upper surface 106 (e.g., uniformly formed on the upper surface
106). For example, forming recessed features 108 in the radially
inner half of the upper surface 106 may act as a redundant
spallation limiting structure for the plurality of recessed
features 108 formed in the radially outer half of the upper surface
106.
In an embodiment, at least some of the plurality of recessed
features 108 may extend to an outer edge of the upper surface 106.
However, at least some of the plurality of recessed features 108
may extend to other portions of the PCD table 102. For example, at
least some of the plurality of recessed features 108 may extend
from a location on the upper surface 106 to a location inwardly
from outer edge of the upper surface 106. In another example, at
least some of the plurality of recessed features 108 may extend
from a location on the upper surface 106 to a location beyond the
outer edge of the upper surface 106, such as to a location on the
chamfer 114 or a location on the at least one lateral surface
112.
The ability of the plurality of recessed features 108 to attract
cracks and/or limits spallation may be dependent on the plurality
of recessed features' 108 stress concentration factor. In an
embodiment, the stress concentration factor of the plurality of
recessed features 108 may increase as a ratio of the average depth
of the plurality of recessed features 108 to an average width of
the plurality of recessed features 108 increases. For example, the
ratio may be at least about 1, at least about 1.5, at least about
2, at least about 3, or about 1.5 to about 3.
The plurality of recessed features 108 may exhibit a spacing
therebetween configured to cause cracks formed at or near the leach
boundary-wear intersection location 124 to be attracted to the
nearest recessed feature 108. In an embodiment, two substantially
similar immediately adjacent recessed features may be substantially
parallel along a selected length thereof. The distance between the
substantially parallel lengths of the two immediately adjacent
recessed features may be less than about 3 mm, such as less than
about 2 mm, less than about 1 mm, about 1 mm to about 3 mm, or
about 0.5 mm to about 2 mm. The inventors have found that the two
recessed features can exhibit a microscopic spacing therebetween
and a propagating crack is still attracted to the nearest recessed
feature. In particular, the inventors have found that the two
recessed features may exhibit a spacing therebetween of about 650
.mu.m or less (e.g., about 625 .mu.m or less, about 600 .mu.m or
less, about 500 .mu.m or less, about 400 .mu.m or less, about 300
.mu.m or less, or about 250 .mu.m or less, about 250 .mu.m to about
500 .mu.m, or about 300 .mu.m to about 500 .mu.m) and the
propagating crack can still be attracted to the nearest recessed
feature.
Referring to FIG. 1A, the upper surface 106 may include a plurality
of cells 128 (e.g., closed cells or partially closed cells) formed
therein. The plurality of cells 128 may be at least partially
defined by the plurality of recessed features 108. At least some of
the plurality of cells 128 may also be partially defined by at
least one of the at least one lateral surface 112 and/or the
optional chamfer 114. Each of the plurality of cells 128 may define
a portion of the upper surface 106 that may break from the upper
surface 106 when the PCD table 102 spalls. As such, each of the
plurality of cells 128 may be configured to limit a volume or area
of the upper surface 106 that breaks from the upper surface 106.
For example, the plurality of cells 128 may exhibit an average
surface area that is less than about 5% of the surface area of the
upper surface 106. For example, the plurality of cells 128 may
exhibit an average surface area that is less than about 4%, less
than about 3%, less than about 2%, less than about 1%, or about 1%
to about 5% of the surface area of the upper surface 106. For
example, the plurality of cells may exhibit an average surface area
that is greater than about 20 mm.sup.2, about 0.25 mm.sup.2 to
about 20 mm.sup.2, about 10 mm.sup.2 to about 15 mm.sup.2, about 5
mm.sup.2 to about 10 mm.sup.2, about 1 mm.sup.2 to about 5
mm.sup.2, about 2 mm.sup.2 to about 4 mm.sup.2, or about 0.5
mm.sup.2 to about 3 mm.sup.2. As such, when one or more of the
plurality of cells 128 break from the upper surface 106, the
percentage of the total surface area of the upper surface 106
(prior to any wear, damage, or spallation) that breaks away is less
than about 5%, less than about 7.5%, less than about 10%, less than
about 12.5%, less than about 15%, less than about 20%, less than
about 25%, about 5% to about 15%, about 5% to about 10%, about 10%
to about 20%, or about 15% to about 25%. In a specific example, if
the total surface area of the upper surface 106 equals about 201
mm.sup.2, then less than about 5% would be about 10 mm.sup.2 or
less.
FIG. 2 is a side, cross-sectional view of a PDC 200 that includes a
partially leached PCD table 202, according to an embodiment. Except
as otherwise disclosed herein, the PDC 200 may be substantially the
same as or similar to the PDC 100 shown in FIGS. 1A-1B. For
example, the PCD table 202 includes an unleached region 216 that is
bonded to a substrate 104, a leached region 218, and an interface
219 therebetween. The leached region 218 extends inwardly from an
upper surface 206, at least one lateral surface 212, and optionally
a chamfer 214 of the PCD table 202.
FIG. 2 illustrates a predicted initial wear front 220 prior to the
PDC 200 being worn. The predicted initial wear front 220 is shown
as a surface that extends at an angle .theta. relative to the at
least one lateral surface 212. The angle .theta. may be about
10.degree. to about 30.degree., such as about 20.degree.. The
predicted initial wear front 220 may intersect the PCD table 202
(e.g., at a bottommost portion of the chamfer 214). During
operation, the PCD table 202 may generally wear along an expected
wear front 222 that is substantially congruent to the predicted
initial wear front 220. Similar to the PCD table 102 (FIG. 1B), a
leach boundary-wear intersection location 224 may form when the
expected wear front 222 first contacts the unleached region 216.
The PCD table 202 may exhibit an L.sub.1* value, which is the
distance between the predicted initial wear front 220 and the
expected wear front 222 when the expected wear front 222 contacts
the unleached region 216 (e.g., when the angle .theta. is about
20.degree., the shortest distance measured substantially
perpendicularly from the predicted initial wear front 220 to a
portion of the interface 219). In the illustrated embodiment, the
expected wear front 222 contacts the unleached region 216 (where
the interface 219 contacts the at least one lateral surface 212).
As such, unlike the PCD table 102 (FIG. 1B), increasing the first
leach depth D.sub.1, the leach depth measured inwardly from the at
least one lateral surface 212 and/or the leach depth measured
inwardly from the optional chamfer 214 does not increase the
L.sub.1* value. Instead, the L.sub.1* value only increases when the
percentage of the at least one lateral surface 212 is leached.
Therefore, in some embodiments, the L.sub.1* value illustrated in
FIG. 2 may be the maximum possible L.sub.1* value.
The PCD table 202 may include a plurality of recessed features 208
formed in the upper surface 206. In the illustrated embodiment, the
leach boundary-wear intersection location 224 may be spaced
relatively far from the upper surface 206. As such, in an
embodiment, the plurality of recessed features 208 may exhibit a
relatively great depth (e.g., 500 .mu.m or greater), an average
depth that is greater than an average width thereof (e.g., by a
ratio of about 2 or more), and/or another feature configured to
attract cracks to the nearest recessed feature 208 and/or limit
spallation.
FIG. 3 is a schematic illustration of an embodiment of a method for
fabricating a PDC 300 that may be used in any of the embodiments
disclosed herein, according to an embodiment. Referring to FIG. 3,
a mass of diamond particles 330 is positioned adjacent to a
substrate 104. The mass of diamond particles 330 may exhibit an
average particle size of about 0.1 .mu.m to about 150 .mu.m (e.g.,
about 50 .mu.m or less, about 30 .mu.m or less, about 20 .mu.m or
less, about 20 .mu.m to about 18 .mu.m, or about 15 .mu.m to about
18 .mu.m). The diamond particle size distribution of the mass of
diamond particles 330 may exhibit a single mode, or may exhibit a
bimodal or greater grain size distribution. In an embodiment, the
plurality of diamond particles may include a relatively larger size
and at least one relatively smaller size. As used herein, the
phrases "relatively larger" and "relatively smaller" refer to
particles sizes determined by any suitable method, which differ by
at least a factor of two (e.g., 40 .mu.m and 20 .mu.m). In various
embodiments, the diamond particles 330 may include a portion
exhibiting a relatively larger size (e.g., 100 .mu.m, 90 .mu.m, 80
.mu.m 70 .mu.m, 60 .mu.m, 50 .mu.m, 40 .mu.m, 30 .mu.m, 20 .mu.m,
15 .mu.m, 12 .mu.m, 10 .mu.m, 8 .mu.m) and another portion
exhibiting at least one relatively smaller size (e.g., 30 .mu.m, 20
.mu.m, 10 .mu.m, 15 .mu.m, 12 .mu.m, 10 .mu.m, 8 .mu.m, 4 .mu.m, 2
.mu.m, 1 .mu.m, 0.5 .mu.m, less than 0.5 .mu.m, 0.1 .mu.m, less
than 0.1 .mu.m). Of course, the diamond particles 330 may also
include three or more different sizes (e.g., one relatively larger
size and two or more relatively smaller sizes), without limitation.
Examples of diamond particle size distributions for the diamond
particles 300 are disclosed in U.S. Provisional Patent Application
No. 61/948,970, U.S. Provisional Patent Application No. 62/002,001,
U.S. patent application Ser. No. 13/734,354, and U.S. patent
application Ser. No. 14/627,966. The disclosure of each of the
foregoing patent applications is incorporated herein, in its
entirety, by this reference.
In order to effectively HPHT sinter the mass of diamond particles
330, the mass of diamond particles 330 may be placed adjacent a
surface of the substrate 104 to form an assembly 332. The assembly
332 may be placed in a pressure transmitting medium, such as a
refractory metal can, graphite structure, pyrophyllite,
combinations thereof, or another suitable container or supporting
element. The pressure transmitting medium, including the assembly
332, may be subjected to an HPHT process at a temperature of at
least about 1000.degree. C. (e.g., about 1100.degree. C. to about
2200.degree. C., or about 1200.degree. C. to about 1450.degree. C.)
and a pressure in the pressure transmitting medium of at least
about 5 GPa (e.g., at least about 7.5 GPa, at least about 9.0 GPa,
at least about 10.0 GPa, at least about 11.0 GPa, at least about
12.0 GPa, at least about 14.0, or about 7.5 GPa to about 9.0 GPa)
for a time sufficient to sinter the diamond particles 330 and form
a PCD table 302 bonded to the substrate 104 thereby forming the PDC
300.
During the HPHT process, the presence of a catalyst facilitates
intergrowth between the mass of diamond particles 330 and forms the
PCD table 302 including directly bonded-together diamond grains
(e.g., exhibiting sp.sup.3 bonding) defining a plurality of
interstitial regions. In the illustrated embodiment, the PDC 300
may be formed by sintering the mass of diamond particles 330 on the
substrate 104, which may be a cobalt-cemented tungsten carbide
substrate. For example, cobalt and/or a cobalt alloy from the
substrate 104 liquefies during the HPHT process and infiltrates
into the mass of diamond particles 330 to catalyze formation of the
PCD table 302. In such an example, some tungsten and/or tungsten
carbide (metallic infiltrants) from the substrate 104 may dissolve
in or otherwise transfer or alloy with the catalyst. However, in
other embodiments, the catalyst may be mixed with the mass of
diamond particles 330, provided from a thin foil, another external
source, or combinations thereof. Additionally, the catalyst and the
metallic infiltrants may react with the mass of diamond particles
330 to form carbides. As such, the interstitial regions of the PCD
table 302 may be at least partially occupied by at least one
interstitial constituent (e.g., at least one of a metal-solvent
catalyst, a metallic infiltrant, one or more formed carbides
etc.).
The PCD table 302 so formed may include an interfacial surface 310
bonded to the substrate 104. Examples of interfacial surface
geometries for the substrate 104 that may be bonded to the
interfacial surface 310 are disclosed in U.S. Pat. No. 8,297,382,
the disclosure of which is incorporated herein, in its entirety, by
this reference. The PCD table 302 may include an upper surface 306
spaced from the interfacial surface 310 and at least one lateral
surface 312 extending between the upper surface 306 and the
interfacial surface 310. In an embodiment, the sintered grains of
the PCD table 302 may exhibit an average grain size of about 20
.mu.m or less or about 30 .mu.m or less. For example, the average
grain size and grain size distribution of the PCD table 302 may be
substantially similar or the same as the average diamond particle
size and distribution of the mass of diamond particles 330.
Examples of suitable HPHT process conditions that may be used to
form any of the PDC embodiments disclosed herein are disclosed in
U.S. Pat. No. 7,866,418 which is incorporated herein, in its
entirety, by this reference.
After the HPHT process, the PDC 300 may be subsequently shaped to
include an optional peripherally-extending chamfer 314. Further, as
previously described, the PCD table 302 may be at least partially
leached to remove at least a portion of the at least one
interstitial constituent therefrom. In an embodiment, the PDC 300
may be at least partially immersed in and/or exposed to a leaching
agent (e.g., hydrofluoric acid, nitric acid, a supercritical fluid,
a gaseous leaching agent, another suitable leaching agent, or
combinations thereof) to at least partially remove at least one
interstitial constituent from the PCD table 302 to form a leached
region (e.g., leach regions 118, 218 of FIGS. 1B-2). Removing at
least a portion of the at least one interstitial constituent from
the PCD table 302 may improve the wear resistance, heat resistance,
thermal stability, or combinations thereof of the PCD table 302,
particularly in situations where the PCD table 302 may be exposed
to elevated temperatures.
In an embodiment, the PCD table 302 may include a plurality of
recessed features 308 formed in the upper surface 306 thereof after
the PCD table 302 is at least partially leached. For example, the
plurality of recessed features 308 may be formed in the upper
surface 306 by grinding or machining, such as at least one of laser
machining, electrical discharge machining, or water jet machining.
Examples of methods of using a laser to cut or machine a PCD table
are disclosed in U.S. Pat. No. 9,062,505, the disclosure of which
is incorporated herein, in its entirety, by this reference. In
another example, the plurality of recessed features 308 may be
formed in the upper surface 306 using acid etching, plasma etching,
or other suitable etching techniques. Forming the plurality of
recessed features 308 after leaching the PCD table 302 may result
in a leached region that exhibits a first leach depth D.sub.1 and a
second leach depth D.sub.2 that is less than the first leach depth
D.sub.1 (FIG. 1B).
In another embodiment, the PCD table 302 may have the plurality of
recessed features 308 formed in the upper surface 306 prior to
leaching the PCD table 302. In such an embodiment, the plurality of
recessed features 308 may be formed using any of the methods
disclosed above. Additionally, the plurality of recessed features
308 may be formed using electrical discharge machining (e.g., wire
electrical discharge machining) or pressed into the diamond
particles before and/or during the HPHT process. The PCD table 302
including the plurality of recessed features 308 formed therein may
then be leached using any of the leaching techniques disclosed
herein. Forming the plurality of recessed features 308 prior to
leaching the PCD table 302 may result in a leached region that
exhibits a substantially uniform leach depth extending inwardly
from the upper surface 306 and a base of each of the plurality of
recessed features 308. For example, the leached region may be
generally complementary to the topography of the outer surface of
the top/upper surface of the PCD table 302 including surfaces
formed by the recessed features 308.
In an embodiment, the plurality of recessed features 308 are formed
in the upper surface 306 after leaching. For example, the plurality
of recessed features 308 formed after leaching may be closer to a
leach boundary-wear intersection location than if recessed features
308 were formed prior to leaching. As such, the plurality of
recessed features 308 formed after leaching may exhibit a smaller
average depth than the plurality of recessed features 308 formed
prior to leaching.
Any of the recessed features disclosed herein may exhibit a number
of suitable side, cross-sectional geometries. For example, any of
the PCD tables disclosed herein may include a first plurality of
recessed features that exhibits a first cross-sectional geometry
(in side view) and a second plurality of recessed features that
exhibits a second cross-sectional geometry (in side view) that is
different than the first cross-sectional geometry. In another
example, any of the PCD table disclosed herein may include a
plurality of recessed features that each exhibits a substantially
similar cross-sectional geometry. FIGS. 4A-4C are partial, side,
cross-sectional of PCD tables that include at least one recessed
feature formed therein that each exhibit different cross-sectional
geometries, according to different embodiments. The PCD tables
illustrated in FIGS. 4A-4C may be substantially the same as or
similar to the PCD tables 102, 202, 302 (FIGS. 1A-3). Similarly,
the cross-sectional geometries (in side view) of the recessed
features illustrated in FIGS. 4A-4C may be used in any of the
embodiments disclosed herein.
Referring to FIG. 4A, a PCD table 402a includes a leached region
418a and an unleached region 416a. The leached region 418a extends
inwardly from an upper surface 406a of the PCD table 402a. The PCD
table 402a also includes at least one recessed feature 408a formed
in and extending inwardly from the upper surface 406a.
In the illustrated embodiment, the at least one recessed feature
408a exhibits a generally rectangular cross-sectional geometry (in
side view). The generally rectangular cross-sectional geometry of
the at least one recessed feature 408a may include a base 426a
having a length and at least two side surfaces 434a extending from
the base 426a to the upper surface 406a. The at least two side
surfaces 434a may be substantially parallel, slightly diverge, or
slightly converge relative to each other. In an embodiment, the at
least two side surfaces 434a may also extend substantially
perpendicularly or at an oblique angle relative to the upper
surface 406a and/or the base 426a.
The generally rectangular cross-sectional geometry of the at least
one recessed feature 408a may also include at least two corners
436a where the at least two side surfaces 434a meet the base 426a.
The corners 436a may exhibit a radius of curvature, a fillet, or
any other geometry. For example, at least one of the corners 436a
may exhibit a relatively small radius of curvature when the corner
436a is sharp or exhibit a relatively large radius of curvature
when the corner 436a is rounded. The radius of curvature of the
corners 436a may correspond to a stress concentration factor
exhibited by the corners. For example, a corner 436a that is sharp
is expected to exhibit a relatively larger stress concentration
factor than a corner 436a that is rounded. As such, a corner 436a
may exhibit a sharp corner when the at least one recessed feature
408a is spaced relatively far from a leach boundary-wear
intersection location. In an embodiment, the at least one recessed
feature 408a may include a first corner that is relatively sharp
and a second corner that is relatively round. In another
embodiment, the at least one recessed feature 408a may only exhibit
a relatively sharp corner along a selected length of the at least
one recessed feature 408a.
Referring to FIG. 4B, a PCD table 402b includes a leached region
418b and an unleached region 416b. The leached region 418b extends
inwardly from an upper surface 406b of the PCD table 402b. The PCD
table 402b also includes at least one recessed feature 408b formed
in and extending inwardly from the upper surface 406b.
The at least one recessed feature 408b exhibits a cross-sectional
geometry (in side view) that is generally v-shaped. The generally
v-shaped cross-sectional geometry may include at least two side
walls 434b that extend and diverge from a base 426b to the upper
surface 406b. At least one of the two side walls 434b may exhibit
an oblique angle relative to the upper surface 406b. In the
illustrated embodiment, the base 426b of the at least one recessed
feature 408b exhibits a corner 436b. Similar to the at least two
corners 436a (FIG. 4A), the corner 436b may be sharp or rounded.
For example, the corner 436b may be sharp if the corner 436b is
relatively spaced from a leach boundary-wear intersection
location.
Referring to FIG. 4C, the PCD table 402c includes a leached region
418c and an unleached region 416c. The leached region 418c extends
inwardly from an upper surface 406c of the PCD table 402c. The PCD
table 402c also includes at least one recessed feature 408c formed
in and extending inwardly from the upper surface 406c.
The at least one recessed feature 408c exhibits a cross-sectional
geometry (in side view) that is arcuate (e.g., generally partially
elliptical, such as partially circular). As such, the at least one
recessed feature 408c may include a single continuous wall 434c
that exhibits a generally concave shape relative to the upper
surface 406c. Since the at least one recessed feature 408c does not
include any corners, the at least one recessed feature 408c may
exhibits a relatively low stress concentration factor. However,
cracks formed in the PCD table 402c may be preferentially attracted
to the at least one recessed feature 408c at least partially due to
a proximity of the at least one recessed feature 408c to the
crack.
Any of the recessed features disclosed herein (e.g., grooves,
recesses, notches, dimples, channels, or networks) may exhibit any
suitable pattern or network when formed in an upper surface of a
PCD table. FIGS. 5-10E are top plan views of different PCD tables
that exhibit different patterns of the plurality of recessed
features formed in an upper surface thereof, according to different
embodiments. The PCD tables illustrated in FIGS. 5-10E may be
substantially the same as or similar to the PCD tables 102, 202,
302, 402a-c (FIGS. 1-4C). For example, the PCD tables may be a
partially leached PCD table that is bonded to a substrate. Any of
the patterns illustrated in FIGS. 5-10E may be used in any of the
embodiments disclosed herein. Additionally, any one or more of the
patterns illustrated in FIGS. 5-10E or portions thereof may be
combined together, without limitation.
Referring to FIG. 5, a PCD table 502 includes a plurality of
recessed features 508 formed in an upper surface 506 thereof. The
plurality of recessed features 508 form a generally triangular
shape that is centered about a location on the upper surface 506
(e.g., a center of the upper surface 506). However, the plurality
of recessed features 508 may form any other suitable shape, such as
a generally circular shape, a generally rectangular shape, a
generally pentagonal shape, a generally hexagonal shape, a
generally elliptical shape, a generally crescent shape, or any
other suitable shape. In the illustrated embodiment, the plurality
of recessed features 508 only form a plane figure shape. However,
the plurality of recessed features 508 may form a plurality of
shapes that are each oriented differently (e.g., rotated, centered
about a different location), exhibit different sizes, exhibit
different shapes, intersect each other, or combinations
thereof.
In the illustrated embodiment, the plurality of recessed features
508 extend from and contact an outer edge of the upper surface 506.
As such, the plurality of recessed features 508 form four cells
528. Three of the cells 528 are formed along the outer edge of the
upper surface 506 and form three distinct cutting surfaces. The
plurality of recessed features 508 may limit spalling of one of the
cells 528 from significantly adversely affecting the other cells
528. Additionally, the four cells 528 may limit spalling in a
radial direction more than in a circumferential direction. Other
patterns may form more or less cells and increase or decrease the
amount of spalling in a radial and/or circumferential
direction.
Referring to FIG. 6, a PCD table 602 includes a plurality of
recessed features 608 formed in an upper surface 606 thereof. The
plurality of recessed features 608 may extend radially from and/or
relative to a location on the upper surface 606 (e.g., a center of
the upper surface 606) to form a generally spoke-like pattern. As
such, the plurality of recessed features 608 may form a plurality
of cells 628 that may limit spalling along a circumferential
direction. In an embodiment, the plurality of recessed features 608
may be substantially straight, curved, exhibit an "S" shape, or any
other suitable shape. In an embodiment, each of the plurality of
recessed features 608 may be angularly equidistantly spaced from
each other. In another embodiment, at least some of the plurality
of recessed features 608 may not be angularly equidistantly spaced
from each other. In an embodiment, an angular spacing between two
adjacent recessed features 608 may be equal to or greater than an
angular spacing of an expected wear front in the PCD table 602 when
the PCD table 602 is expected to spall.
FIGS. 7A-7D illustrate different embodiments in which a plurality
of recessed features form different grid-like patterns in a PCD
table. The grid-like patterns illustrated in FIGS. 7A-7D may
substantially equally limit spalling of the PCD table in a
circumferential and radial direction. Referring to FIG. 7A, a PCD
table 702a may include a plurality of recessed features 708a formed
in an upper surface 706a thereof. The plurality of recessed
features 708a includes a plurality of first recessed features 708a'
that extend substantially parallel to each other and a plurality of
second recessed features 708a'' that extend substantially parallel
to each other and substantially orthogonally relative to the
plurality of first recessed features 708a'. As such, the plurality
of recessed features 708a form a plurality of generally rectangular
cells 728a that form a generally rectangular grid-like pattern.
However, in an embodiment, the plurality of first and second
recessed features 708a', 708a'' extend obliquely relative to each
other.
Referring to FIG. 7B, a PCD table 702b may include a plurality of
recessed features 708b formed in an upper surface 706b thereof. The
plurality of recessed features 708b includes plurality of first
recessed features 708b' that extend substantially parallel to each
other, a plurality of second recessed features 708b'' that extend
substantially parallel to each other, and a plurality of third
recessed features 708b''' that extend substantially parallel to
each other. In an embodiment, each of the plurality of first,
second, and third recessed features 708b', 708b'', 708b''' may
extend obliquely relative to each other. In another embodiment, two
of the plurality of first, second, or third recessed features
708b', 708b'', 708b''' may extend substantially orthogonally
relative to each other. In an embodiment, the plurality of recessed
features 708b may form a plurality of generally triangular cells
728b that form a generally triangular grid-like pattern.
Referring to FIG. 7C, a PCD table 702c may include a plurality of
recessed features 708c formed in an upper surface 706c thereof. The
plurality of recessed features 708c form a plurality of generally
hexagonal cells 728c that form a grid-like pattern.
Referring to FIG. 7D, a PCD table 702d may include a plurality of
recessed features 708d formed in an upper surface 706d thereof. At
least some of the plurality of recessed features 708d may be
curved. In the illustrated embodiment, each of the plurality of
recessed features 708d extend from at least two locations (e.g.,
eight locations) positioned at or near an outer edge of the upper
surface 706d. The plurality of recessed features 708d may extend
between generally opposite locations in substantially the same
manner as longitudinal lines on an equatorial Robinson projection,
an equatorial Winkel tripel projection, an equatorial azimuthal
equidistant projection, an equatorial stereographic projection, an
equal-area Mollweide projection, etc. As such, a concentration of
the plurality of recessed features 708d may be greatest at or near
the at least two locations. Additionally, the concentration of the
plurality of recessed features 708d may be greater at and near the
edge of the upper surface 706d than at a center of the upper
surface 706d.
FIGS. 8A-8C illustrate different embodiments in which a plurality
of recessed features form a generally two-dimensional or
three-dimensional spiral pattern. The generally spiral pattern of
the plurality of recessed features may limit spalling of the PCD
table in a circumferential and radial direction. Referring to FIG.
8A, a PCD table 802a may include a plurality of recessed features
808a formed in an upper surface 806a thereof. The plurality of
recessed features 808a may extend in a spiral from and/or relative
to a location or area on the upper surface 806a (e.g., a center of
the upper surface 806a). In an embodiment, each of the plurality of
recessed features 808a may be equidistantly spaced from each other.
In another embodiment, at least some of the plurality of recessed
features 808a may not be equidistantly spaced from each other. In
an embodiment, a circumferential spacing between two adjacent
recessed features 808a may be equal to or greater than a
circumferential width of an expected wear front in the PCD table
802a when the PCD table 802a is expected to spall.
Referring to FIG. 8B, a PCD table 802b may include a plurality of
recessed features 808b formed in an upper surface 806b thereof. The
plurality of recessed features 808b may include a plurality of
first recessed features 808b' and a plurality of second recessed
features 808b''. The plurality of first recessed features 808b' may
be substantially the same as or similar to the plurality of
recessed features 808a (FIG. 8A). For example, the plurality of
first recessed features 808b' may extend along a spiral from a
location or area on the upper surface 806b. The plurality of second
recessed features 808b'' may extend between at least some of the
plurality of first recessed features 808b' (e.g., generally
crosswise or transverse to the first recessed features 808b'). As
such, the plurality of second recessed features 808b'' may further
limit the spalling in a circumferential and radial direction
compared to the plurality of recessed features 808a (FIG. 8A).
Referring to FIG. 8C, a PCD table 802c may include a plurality of
recessed features 808c formed in an upper surface 806c thereof. The
plurality of recessed features 808c may extend along a spiral from
a location or area on the upper surface 806c (e.g., a center of the
upper surface 806c). However, the plurality of recessed features
808c may be relatively angular and/or discontinuous. The plurality
of recessed features 808c may also include a plurality of recessed
features that extend between the plurality of recessed features
808c.
FIGS. 8D-8I illustrate different PCD tables 802d-i that include a
plurality of recessed features 808d-i formed in an upper surface
806d-i thereof. The plurality of recessed features 808d-i shown in
FIGS. 8D-8I are embodiments of different spiral patterns that the
plurality of recessed features 808d-i may form. Additionally, each
of the plurality of recessed features 808d-i may be discontinuous
recessed features (e.g., formed from a plurality of notches,
dimples, recesses, or divots). In an embodiment, at least some of
the plurality of recessed features 808d-i may be formed
sufficiently close together that the at least some of the plurality
of recessed features 808d-i forms a continuous feature (e.g., the
plurality of recessed features 800d, 808g-i of FIGS. 8D, 8G-8I). In
another embodiment, the plurality of notches may be uniformly
distributed across the upper surface (e.g., the plurality of
recessed features 808f of FIG. 8F). It is noted that any of the
recessed features disclosed herein may be formed from a plurality
of notches, dimples, recesses, or divots. It is also noted that any
of the spiral patterns shown in FIGS. 8D-8I may be at least
partially formed (e.g., completely formed) from a continuous
channel instead of the plurality of notches, dimples, recesses, or
divots. In some embodiments, a plurality of recessed features may
include at least one substantially continuous recessed feature
(e.g., at least one groove, at least one channel, etc.) and at
least one discrete recessed feature (e.g., at least one notch,
dimple, recess, or divot).
FIGS. 9A-9D illustrate different embodiments in which a plurality
of recessed features form a plurality of generally concentric
shapes that may limit spalling in at least a radial direction.
Referring to FIG. 9A, a PCD table 902a may include a plurality of
recessed features 908a formed in an upper surface 906a thereof. The
plurality of recessed features 908a may form a plurality of
generally rectangular shapes that are generally concentric relative
to a location on the upper surface 906a such as a center of the
upper surface 906a. The generally rectangular shapes formed by the
plurality of recessed features 908a may form a plurality of cells
928a, four of which are adjacent to an outer edge of the upper
surface 906a. The four cells 928a may partially define four
distinct cutting surfaces that may each spall without substantially
adversely affecting the others. In operation, the outermost
generally rectangular shape may be configured to limit spalling in
a direction generally radially inwardly. However, the other
generally rectangular shapes spaced inwardly from the outermost
generally rectangular shape may be configured to further limit
spalling in a general radial direction if the spalling extends past
the outermost generally rectangular shape.
The plurality of recessed features 908a may form any suitable
shapes (e.g., generally geometrically expanding or contracting
shapes centered about a common point). For example, the plurality
of recessed features 908a may form a generally circular shape, a
generally rectangular shape, a generally pentagonal shape, a
generally hexagonal shape, a generally elliptical shape, a
generally crescent shape, or any other suitable shape. In an
embodiment, the plurality of recessed features 908a may form a
plurality of different shapes that are generally centered about a
common point relative to each other. For example, the plurality of
recessed features 908a may form an outermost shape that is
generally rectangular and another shape that is inwardly generally
centered relative to the outermost shape that is generally
triangular. In an embodiment, at least one of the generally
rectangular shapes may be rotated relative to the outermost
generally rectangular shape.
Referring to FIG. 9B, a PCD table 902b includes a plurality of
recessed features 908b formed in an upper surface 906b thereof. The
plurality of recessed features 908b may include a plurality of
first recessed features 908b' and a plurality of second recessed
features 908b''. The plurality of first recessed features 908b' may
form a plurality of shapes centered about a common point, such as a
plurality of concentric generally circular shapes. The plurality of
first recessed features 908b' may be generally concentric relative
to a location on the upper surface 906b (e.g., a center of the
upper surface 906b). The plurality of second recessed features
908b'' may be substantially the same as or similar to the plurality
of recessed features 608 (FIG. 6). For example, the plurality of
second recessed features 908b'' may extend from the same common
point on the upper surface 906b that the plurality of first
recessed features 908b' are centered about or extend from another
location on the upper surface 906b.
The plurality of recessed features 908b illustrate an example of
combining two of the patterns disclosed herein to form a single
pattern. As such, the plurality of recessed features 908b may
exhibit the benefits of the pattern discussed in FIG. 6 and the
generally concentric shapes discussed in FIG. 9A. For example, the
plurality of first recessed features 908b' may limit spalling in a
radial direction while the plurality of second recessed features
908b'' may limit spalling in a circumferential direction.
In an embodiment, the plurality of first recessed features 908b'
may not include a plurality of generally commonly centered shapes.
Instead, the plurality of first recessed features 908b' may include
a plurality of linear, convexly curved, and/or concavely recessed
features that extend between the plurality of second recessed
features 908b'' in any suitable manner. For example, the plurality
of first recessed features 908b' may form a plurality of shapes
that are not generally centered with respect to each other. In
another example, at least some of the plurality of first recessed
features 908b' may be radially offset from a circumferentially
adjacent first recessed feature 908b' (e.g., at least some of the
plurality of first recessed features 908b' may not form continuous
shapes).
Referring to FIG. 9C, a PCD table 902c includes a plurality of
recessed features 908c formed in an upper surface 906c thereof. The
plurality of recessed features 908c include a plurality of first
recessed features 908c', a plurality of second recessed features
908c'', and a plurality of third recessed features 908c'''. The
plurality of first recessed features 908c' may be substantially
similar to the plurality of recessed features 908a (FIG. 9A). For
example, the plurality of first recessed features 908c' may include
a plurality of generally commonly centered shapes, such as a
plurality of concentric generally rectangular shapes. The outermost
concentric generally rectangular shape may define four cells 928c
adjacent to an outer edge of the upper surface 906c. The plurality
of second recessed features 908c'' may include a plurality of
generally concentric shapes that are different than the plurality
of first recessed features 908c'. For example, the plurality of
second recessed features 908c'' may be a plurality of concentric
generally circular shapes. The plurality of second recessed
features 908c'' may be positioned between the shapes formed by the
plurality of first recessed features 908c'. Finally, the plurality
of third recessed features 908c''' form a plurality of
radially-extending recessed features (e.g., a generally spoke-like
pattern) that extend from a common location on the upper surface
906c.
The plurality of recessed features 908c'-908c''' illustrate an
example of combining three patterns to form a single network or
pattern. For example, the plurality of first recessed features
908c' may limit spalling in a generally radial direction and the
plurality of third recessed features 908c''' may limit spalling in
a generally circumferential direction. The plurality of first,
second, and third recessed features 908c', 908c'', 908c''' may form
further spall-limiting features.
Referring to FIG. 9D, a PCD table 902d includes a plurality of
recessed features 908d formed in an upper surface 906d thereof. The
plurality of recessed features 908d may include a plurality of
first recessed features 908d' and a plurality of second recessed
features 908d''. The plurality of first recessed features 908d' may
be substantially similar to the plurality of recessed features 708d
(FIG. 7D). For example, the plurality of first recessed features
908d' may include a plurality of curved recessed features extending
between two locations (e.g., end locations 909 and 911). The
plurality of second recessed features 908d'' may form a plurality
of generally concentric shapes, such as a plurality of generally
concentric arcs that are generally centered about a common location
(e.g., end locations 909, 911, a location on the upper surface 906d
or a location off the upper surface 906d). For example, the
location may be at one of the two locations that the plurality of
first recessed features 908d' extend from and/or between. The
plurality of first and second recessed features 908d', 908d'' may
form a pattern exhibiting a higher concentration of recessed
features near the outer edge of the upper surface 906d than
relative to a concentration of recessed features near center of the
upper surface 906d. Additionally, the plurality of first and second
recessed features 908d', 908d'' form a pattern exhibiting a higher
concentration of recessed features near the end locations 909 and
911. As such, the plurality of first and second recessed features
908d', 908d'' may limit spalling to a greater extent near the end
locations 909, 911 than near the center of the upper surface
906d.
FIGS. 10A-10E illustrate different embodiments where a plurality of
recessed features form a generally hypocycloid or hypotrochoid
pattern. FIG. 10A illustrates a PCD table 1002a that includes a
plurality of recessed features 1008a formed in an upper surface
1006a thereof. The plurality of recessed features 1008a may include
a plurality of generally arcuately-extending concavely or convexly
curved recessed features (e.g., extending between cusps thereof)
that, optionally, at least intersect with another recessed feature
to form a cusp. In an embodiment, at least some of the plurality of
recessed features 1008a may exhibit a different distance between
the cusps thereof, a different radius of curvature, and/or a
different length. In an embodiment, the plurality of recessed
features 1008a may be substantially the same and form a hypocycloid
or a hypotrochoid. For example, in the illustrated embodiment, the
plurality of recessed features 1008a form a generally hypocycloid
shape. However, in other embodiments, the plurality of recessed
features 1008a form a generally hypotrochoid shape, a generally
epicycloid shape, a generally epitrochoid shape, another suitable
cycloid, or another suitable trochoid. During operation, the
plurality of recessed features 1008a may limit spalling in a radial
direction and a circumferential direction.
In an embodiment, the plurality of recessed features 1008a may form
a shape (e.g., cycloid or trochoid) having at least 3 cusps, such
as 4, 5, 5-10, 10-15, 15-20, or greater than 20 cusps. The number
of cusps of the shape formed from the plurality of recessed
features 1008a may correspond to the number of cells 1028a formed
radially outwardly from the shape. In an embodiment, the plurality
of recessed features 1008a may optionally intersect at the cusps
thereof or the plurality of recessed features 1008a may optionally
intersect at the cusps thereof and at one or more locations between
the cusps thereof.
Referring to FIG. 10B, a PCD table 1002b includes a plurality of
recessed features 1008b formed in an upper surface 1006b thereof.
As shown in FIG. 10B, the plurality of recessed features 1008b
include a plurality of generally arcuately-extending curved
recessed features that intersect at cusps thereof. Similar to the
plurality of recessed features 1008a (FIG. 10A), at least some of
the plurality of recessed features 1008b may form one or more
hypocycloids, hypotrochoids, or another suitable shape. The cusps
of at least some of the plurality of recessed features 1008b may
contact one or more radially inwardly or outwardly adjacent
recessed features 1008b. As such, the plurality of recessed
features 1008b may form a generally scale-like pattern (e.g., a
plurality of contiguous hypocycloids). FIG. 10C also illustrates a
plurality of recessed features 1008c formed in an upper surface
1006c of PCD table 1002c that include a plurality of generally
extending curved recessed features that intersect at cusps thereof.
The plurality of recessed features 1008c may form a plurality of
generally concentric shapes (e.g., cycloids and/or trochoids).
However, in some embodiments, the plurality of generally concentric
shapes may not contact a radially adjacent recessed feature
1008c.
Referring to FIG. 10D, a PCD table 1002d includes a plurality of
recessed features 1008d formed in an upper surface 1006d thereof.
The plurality of recessed features 1008d may form a plurality of
first recessed features 1008d' and a plurality of second recessed
features 1008d''. The plurality of first recessed features 1008d'
may be substantially similar to the plurality of recessed features
1008a (FIG. 10B). For example, the plurality of first recessed
features 1008d' may include a plurality recessed features that
intersect at the cusps thereof and contact one or more radially
adjacent recessed features 1008d'. The plurality of second recessed
features 1008d'' may be substantially similar to the plurality of
recessed features 608 (FIG. 6). For example, the plurality of
second recessed features 1008d'' may form a generally spoke-like
pattern. As such, the plurality of second recessed features 1008d''
may further limit spalling in a circumferential direction compared
to the plurality of recessed features 1008b (FIG. 10B).
Referring to FIG. 10E, a PCD table 1002e includes a plurality of
recessed features 1008e formed in an upper surface 1006e thereof.
The plurality of recessed features 1008e include a plurality of
first recessed features 1008e' and a plurality of second recessed
features 1008e''. The plurality of first recessed features 1008e'
may be substantially similar to the plurality of recessed features
1008c (FIG. 10C). For example, the plurality of first recessed
features 1008e' may include a plurality of generally
arcuatedly-extending curved recessed features that intersect at the
cusps thereof. The plurality of first recessed features 1008e' may
form a plurality of generally commonly-centered shapes (e.g.,
cycloids and/or trochoids). The plurality of second recessed
features 1008e'' may be substantially similar to the plurality of
second recessed features 1008d'' (FIG. 10D). As such, the plurality
of recessed features 1008e may form a generally web-like pattern.
The plurality of first recessed features 1008e' may limit spalling
generally in a radial direction and the plurality of second
recessed features 1008e'' may limit spalling generally in a
circumferential direction.
In an embodiment, the plurality of first recessed features 1008e'
may not form a plurality of generally concentric shapes. Instead,
the plurality of first recessed features 1008e' may include a
plurality of curved recessed features that extend between the
plurality of second recessed features 1008e''. For example, at
least some of the plurality of first recessed features 1008e' may
not intersect at the cusp thereof and may be radially spaced
relative to a circumferentially adjacent first recessed feature
1008e'.
The following working examples of the present disclosure set forth
various configurations that have been used to form the PDC cutting
elements disclosed herein. The following working examples provide
further detail in connection with the embodiments described
above.
Comparative Example 1
A conventional PDC was formed from a bimodal mixture of diamond
particles having respective modes at about 30 .mu.m and about 2
.mu.m. The mixture of diamond particles was positioned adjacent to
a cobalt-cemented tungsten carbide substrate. The plurality of
diamond particles were sintered and bonded to the substrate in an
HPHT process having a cell pressure of about 7.8 GPa and a
temperature of about 1360.degree. C. to form the conventional PDC
including a PCD table. The PDC table was then partially leached to
form a leached region having a first leach depth from an upper
surface of the PCD table of about 490 .mu.m, a side leach depth of
about 80 .mu.m, and a L.sub.1* value of about 200 .mu.m. The
conventional PDC did not have any recessed features formed in an
upper surface thereof.
The conventional PDC was then subjected to a milling spallation
test in which the PDC was used to cut a Barre granite workpiece.
The test parameters used for the milling test were a back rake
angle for the PDC of about 20.degree., an in-feed for the PDC of
about 50.8 cm/min, a rotary speed on the workpiece of about 3000
RPM, an indexing across the workpiece (e.g., in the Y direction) of
about 7.62 cm, about 3-5 seconds (no more than 10 seconds) between
cutting passes, and the size of the Barre granite workpiece was
about 63.5 cm by about 48.3 cm. The PDCs were held in a cutting
tool holder, with the substrate of the PDCs tested thermally
insulated on its back side via an alumina disc and along its
circumference by a plurality of zirconia pins. The conventional PDC
was subject to the milling test until the conventional PDC spalled.
Spalling of the PDC was determined using a "burnout" method in
which spalling was detected when at least one of the operator
detected sparks, the operator noticed black marks on the Barre
granite, a sharp rise in the detected temperature, or a slight
change in the force measurements.
FIG. 11 is a photograph of the conventional PDC after the
conventional PDC spalled. FIG. 11 illustrates that the spalled
conventional PDC includes a spalled region that extended
significantly into the PCD table in both a radial direction and a
circumferential direction. Additionally, the PCD table included a
plurality of cracks (e.g., microcracks) that extended from the
spalled region into the PCD table.
Example 2
A PDC was formed as described in comparative example 1 prior to
leaching. The PDC table of example 2 was then partially leached to
form a leached region having a first leach depth from an upper
surface of the PCD table of about 490 .mu.m, a side leach depth of
about 80 .mu.m, and a L.sub.1* value of about 200 .mu.m. A
plurality of recessed features having an average depth of about 75
.mu.m was then formed in the upper surface of the PCD table of
example 2 using a laser. The plurality of recessed features
included a plurality of circumferentially-extending first recessed
features and a plurality of radially-extending second recessed
features that were substantially similar to the plurality of first
recessed features 1008e' and the plurality of second recessed
features 1008e'' (FIG. 10E), respectively. The PDC of example 2 was
then tested in a milling spallation test using the same test
parameters as comparative example 1. The PDC of example 2 was
tested until the PDC of example 2 spalled.
FIG. 12A is a photograph of the PDC of example 2 after the PDC of
example 2 spalled. FIG. 12A illustrates that the spalled PDC of
example 2 included a spalled region that was radially and
circumferentially limited by the plurality of first and second
recessed features, respectively. As such, the spalled region is
partially defined by the plurality of first and second recessed
features. Additionally, the inventors believe that the plurality of
recessed features limited cracks extending from the spalled region
into the PCD table of example 2. As such, the plurality of recessed
features may increase the usability of the PDC of example 2. For
example, the PDC of example 2 can be subjected to another milling
test by rotating the PDC of example 2 such that a portion of the
PCD table of example 2 that does not include the spalled region
forms the cutting contact area.
Example 3
A PDC was formed as described in comparative example 1 prior to
leaching. The PDC table of example 3 was then partially leached to
form a leached region having a first leach depth from an upper
surface of the PCD table of about 490 .mu.m, a side leach depth of
about 80 .mu.m, and a L.sub.1* value of about 200 .mu.m. A
plurality of recessed features having an average depth of about 75
.mu.m was then formed in the upper surface of the PCD table of
example 3 using a laser. The plurality of recessed features
included a plurality of arcuately-extending first recessed features
and a plurality of generally radially-extending second recessed
features (e.g., substantially similar to the plurality of first
recessed features 1008e' and the plurality of second recessed
features 1008e'' (FIG. 10E), respectively). The PDC of example 3
was then tested in milling spallation test using the same test
parameters as comparative example 1. The PDC of example 3 was
tested until the PDC of example 3 spalled.
FIG. 12B is a photograph of the PDC of example 3 after the PDC of
example 3 spalled. FIG. 12B illustrates that the spalled PDC of
example 3 included a spalled region that was radially limited by
the plurality of first recessed features. As such, the spalled
region is partially defined by the plurality of first recessed
features. Additionally, the inventors believe that the plurality of
recessed features limited cracks extending from the spalled region
into the PCD table of example 3. As such, the plurality of recessed
features may increase the usability of the PDC of example 3. For
example, the PDC of example 3 can be subjected to another milling
test by rotating the PDC of example 3 such that a portion of the
PCD table of example 3 that does not include the spalled region
forms the cutting contact area.
Example 4
A PDC was formed as described in comparative example 1 prior to
leaching. The PDC table of example 4 was then partially leached to
form a leached region having a first leach depth from an upper
surface of the PCD table of about 490 .mu.m, a side leach depth of
about 80 .mu.m, and a L.sub.1* value of about 200 .mu.m. A
plurality of recessed features having an average depth of about 75
.mu.m was then formed in the upper surface of the PCD table of
example 4 using a laser. The plurality of recessed features
included a plurality of arcuately-extending first recessed features
and a plurality of generally radially-extending second recessed
features (e.g., substantially similar to the plurality of first
recessed features 1008e' and the plurality of second recessed
features 1008e'' (FIG. 10E), respectively). The PDC of example 4
was then tested in milling spallation test using the same test
parameters as comparative example 1. The PDC of example 4 was
tested until the PDC of example 4 spalled.
FIG. 12C is a photograph of the PDC of example 4 after the PDC of
example 4 spalled. FIG. 12C illustrates that the spalled PDC of
example 4 included a spalled region that was radially and
circumferentially limited by the plurality of first and second
recessed features, respectively. As such, the spalled region is
partially defined by the plurality of first and second recessed
features. Additionally, it is believed by the inventors that the
plurality of recessed features limited cracks extending from the
spalled region into the PCD table of example 4. As such, the
plurality of recessed features may increase the usability of the
PDC of example 4. For example, the PDC of example 4 can be
subjected to another milling test by rotating the PDC of example 4
such that a portion of the PCD table of example 4 that does not
include the spalled region forms the cutting contact surface.
Example 5
A PDC was formed as described in comparative example 1 prior to
leaching. The PDC table of example 5 was then partially leached to
form a leached region having a first leach depth from an upper
surface of the PCD table of about 490 .mu.m, a side leach depth of
about 80 .mu.m, and a L.sub.1* value of about 200 .mu.m. A
plurality of recessed features having an average depth of about 75
.mu.m was then formed in the upper surface of the PCD table of
example 5 using a laser. The plurality of recessed features
included a plurality of arcuately-extending first recessed features
and a plurality of generally radially-extending second recessed
features (e.g., substantially similar to the plurality of first
recessed features 908b' and the plurality of second recessed
features 908b'' (FIG. 9B), respectively). The PDC of example 5 was
then tested in milling spallation test using the same test
parameters as comparative example 1. The PDC of example 5 was
tested in a milling test until the PDC of example 5 spalled.
FIG. 12D is a photograph of the PDC of example 5 after the PDC of
example 5 spalled. FIG. 12D illustrates that the spalled PDC of
example 5 included a spalled region that was radially and
circumferentially limited by the plurality of first and second
recessed features. As such, the spalled region is partially defined
by the plurality of first and second recessed features.
Additionally, the inventors believe that the plurality of recessed
features limited cracks extending from the spalled region into the
PCD table of example 5. As such, the plurality of recessed features
may increase the usability of the PDC of example 5. For example,
the PDC of example 5 can be subjected to another milling test by
rotating the PDC of example 5 such that a portion of the PCD table
of example 5 that does not include the spalled region forms the
cutting contact surface.
Example 6
A PDC was formed as described in comparative example 1 prior to
leaching. The PDC table of example 6 was then partially leached to
form a leached region having a first leach depth from an upper
surface of the PCD table of about 490 .mu.m, a side leach depth of
about 80 .mu.m, and a L.sub.1* value of about 200 .mu.m. A
plurality of recessed features having an average depth of about 75
.mu.m was then formed in the upper surface of the PCD table of
example 6 using a laser. The plurality of recessed features
included a plurality of arcuately-extending first recessed features
and a plurality of generally radially-extending second recessed
features (e.g., substantially similar to the plurality of first
recessed features 908b' and the plurality of second recessed
features 908b'' (FIG. 9B), respectively). The PDC of example 6 was
then tested in milling spallation test using the same test
parameters as comparative example 1. The PDC of example 6 was
tested until the PDC of example 6 spalled.
FIG. 12E is a photograph of the PDC of example 6 after the PDC of
example 6 spalled. FIG. 12E illustrates that the spalled PDC of
example 6 includes a spalled region that was radially and
circumferentially limited by the plurality of first and second
recessed features, respectively. As such, the spalled region is
partially defined by the plurality of first and second recessed
features. FIG. 12E also illustrates how generally commonly centered
shapes may limit spallation. Additionally, it is believed by the
inventors that the plurality of recessed features limited cracks
extending from the spalled region into the PCD table of example 6.
As such, the plurality of recessed features may increase the
usability of the PDC of example 6. For example, the PDC of example
6 can be subjected to another milling test by rotating the PDC of
example 6 such that a portion of the PCD table of example 6 that
does not include the spalled region forms the cutting contact
surface.
Example 7
A PDC was formed as described in comparative example 1 prior to
leaching. The PDC table of example 7 was then partially leached to
form a leached region having a first leach depth from an upper
surface of the PCD table of about 490 .mu.m, a side leach depth of
about 80 .mu.m, and a L.sub.1* value of about 200 .mu.m. A
plurality of recessed features having an average depth of about 75
.mu.m was then formed in the upper surface of the PCD table of
example 7 using a laser. The plurality of recessed features formed
a generally rectangular grid-like pattern (FIG. 7A). The PDC of
example 7 was then tested in milling spallation test using the same
test parameters as comparative example 1. The PDC of example 7 was
tested until the PDC of example 7 spalled.
FIG. 12F is a photograph of the PDC of example 7 after the PDC of
example 7 spalled. FIG. 12F illustrates that the spalled PDC of
example 7 included a spalled region that was radially and
circumferentially limited by the plurality of recessed features. As
such, the spalled region is partially defined by the plurality of
recessed features. Additionally, it is believed by the inventors
that the plurality of recessed features limited cracks extending
from the spalled region into the PCD table of example 7. As such,
the plurality of recessed features may increase the usability of
the PDC of example 7. For example, the PDC of example 7 can be
subjected to another milling test by rotating the PDC of example 7
such that a portion of the PCD table of example 7 that does not
include the spalled region forms the cutting contact surface.
Example 8
A PDC was formed as described in comparative example 1 prior to
leaching. The PDC table of example 8 was then partially leached to
form a leached region having a first leach depth from an upper
surface of the PCD table of about 490 .mu.m, a side leach depth of
about 80 .mu.m, and a L.sub.1* value of about 200 .mu.m. A
plurality of recessed features having an average depth of about 75
.mu.m was then formed in the upper surface of the PCD table of
example 8 using a laser. The plurality of recessed features form a
plurality of generally commonly centered hypocycloids (e.g.,
similar to the plurality of recessed features 1008b (FIG. 10B)).
The PDC of example 8 was then tested in milling spallation test
using the same test parameters as comparative example 1. The PDC of
example 8 was tested until the PDC of example 8 spalled.
FIG. 12G is a photograph of the PDC of example 8 after the PDC of
example 8 spalled. FIG. 12G illustrates that the spalled PDC of
example 8 included a spalled region that was radially and
circumferentially limited by the plurality of first and second
recessed features, respectively. As such, the spalled region is
partially defined by the plurality of first and second recessed
features. The area of the spalled region measured about 19
mm.sup.2, which is about 9.4% of the area of the upper surface of
the PDC of example 8. FIG. 12G also illustrates how generally
concentric shapes may act as fail-safes to an outermost shape.
Additionally, it is believed that the plurality of recessed
features limited cracks extending from the spalled region into the
PCD table of example 8. As such, the plurality of recessed features
may increase the usability of the PDC of example 8. For example,
the PDC of example 8 can be subjected to another milling test by
rotating the PDC of example 8 such that a portion of the PCD table
of example 8 that does not include the spalled region forms the
cutting contact surface.
Example 9
A PDC was formed as described in comparative example 1 prior to
leaching. The PDC table of example 9 was then partially leached to
form a leached region having a first leach depth from an upper
surface of the PCD table of about 490 .mu.m, a side leach depth of
about 80 .mu.m, and a L.sub.1* value of about 200 .mu.m. A
plurality of recessed features having an average depth of about 75
.mu.m was then formed in the upper surface of the PCD table of
example 9 using a laser. The plurality of recessed features
included a plurality of spirally-extending first recessed features
and a plurality of second recessed features extending between the
plurality of first recessed features (e.g., similarly to the
plurality of first recessed features 808b' and the plurality of
second recessed features 808b'' (FIG. 8B), respectively). The PDC
of example 9 was then tested in milling spallation test using the
same test parameters as comparative example 1. The PDC of example 9
was tested until the PDC of example 9 spalled.
The PDC of example 9 included a spalled region that was radially
and circumferentially limited by the plurality of first and second
recessed features, respectively. As such, the spalled region is
partially defined by the plurality of first and second recessed
features. Additionally, it is believed that the plurality of
recessed features limited cracks extending from the spalled region
into the PCD table of example 9. As such, the plurality of recessed
features may increase the usability of the PDC of example 9. For
example, the PDC of example 9 can be subjected to another milling
test by rotating the PDC of example 9 such that a portion of the
PCD table of example 9 that does not include the spalled region
forms the cutting contact surface.
Probability of Failure of Comparative Example 1 and Working
Examples 2, 7, 8 and 9
The thermal stability for several of the PDCs disclosed herein were
measured by determining a distance that the PDCs cut in a mill test
prior to failure. Four PDCs were formed according to the methods
disclosed in each of comparative example 1 and working examples 2,
7, 8, and 9. Each of the PDCs were then subjected to a milling test
in which the PDCs are used to cut the same Barre granite workpiece
without any coolant (e.g., dry cutting of the Barre granite
workpiece in air). The test parameters used for the milling test
were the same as described above in comparative example 1. Failure
is determined when the PDCs can no longer cut the workpiece (e.g.,
spall). Spalling of the PDC was determined using a "burnout" method
where spalling was detected when at least one of the operator
detected sparks, the operator noticed black marks on the Barre
granite, a sharp rise in the detected temperature, or a slight
change in the force measurements. The distance each PDC cut prior
to failure was calculated by: (the width of the
workpiece).times.(the number of complete passes)+(the distance cut
on the last pass prior to failure).
FIG. 13 is a graph showing probability of failure of comparative
example 1 and working examples 2, 7, 8, and 9 versus distance each
PDC cut prior to failure. FIG. 13 illustrates that a probability of
failure at relatively large distances cut for working examples 2,
7, 8, and 9 was superior to comparative example 1. For example, the
graph illustrates that the comparative example 1 exhibited a
probability of failure of about 0.1 at a distance cut of about 305
inches, a probability of failure of about 0.4 at a distance cut of
about 310 inches, and a probability of failure of about 0.75 at a
distance cut of about 315 inches. In contrast, the graph
illustrates that at least some of the working examples exhibit a
probability of failure less than about 0.1 at a distance cut of
about 315 inches or greater (e.g., about 315 inches to about 325
inches, about 325 inches to about 350, about 350 inches or
greater), a probability of failure less than about 0.4 at a
distance cut of about 325 inches or greater (e.g., about 325 inches
to about 350 inches, about 350 inches to about 375 inches, about
375 inches to about 400 inches, greater than 400 inches), a
probability of failure less than about 0.75 at a distance cut of
about 340 inches or greater (e.g., about 350 inches to about 375
inches, about 375 inches to about 400 inches, about 400 inches to
about 425 inches, about 425 inches or greater).
The disclosed PDC embodiments may be used in a number of different
applications including, but not limited to, use in a rotary drill
bit (FIGS. 14A and 14B), a thrust-bearing apparatus, a radial
bearing apparatus, a mining rotary drill bit (e.g., a roof bolt
drill bit), and a wire-drawing die. The various applications
discussed above are merely some examples of applications in which
the PDC embodiments may be used. Other applications are
contemplated, such as employing the disclosed PDC embodiments in
friction stir welding tools.
FIG. 14A is an isometric view and FIG. 14B is a top plan view of an
embodiment of a rotary drill bit 1400 for use in subterranean
drilling applications, such as oil and gas exploration. The rotary
drill bit 1400 includes at least one PCD element and/or PDC
configured according to any of the previously described PDC
embodiments. The rotary drill bit 1400 comprises a bit body 1402
that includes radially and longitudinally extending blades 1404
with leading faces 1406, and a threaded pin connection 1408 for
connecting the bit body 1402 to a drilling string. The bit body
1402 defines a leading end structure for drilling into a
subterranean formation by rotation about a longitudinal axis and
application of weight-on-bit. At least one PDC cutting element,
configured according to any of the previously described PDC
embodiments may be affixed to the bit body 1402.
With reference to FIG. 14B, a plurality of PDCs 1412 are secured to
the blades 1404. For example, each PDC 1412 may include a PCD table
1414 bonded to a substrate 1416. More generally, the PDCs 1412 may
comprise any PDC disclosed herein, without limitation. For example,
the PCD table 1414 may include the plurality of recessed features
1415 formed in an upper surface thereof. In addition, if desired,
in some embodiments, a number of the PDCs 1412 may be conventional
in construction. Also, circumferentially adjacent blades 1404
define so-called junk slots 1418 therebetween, as known in the art.
Additionally, the rotary drill bit 1400 may include a plurality of
nozzle cavities 1420 for communicating drilling fluid from the
interior of the rotary drill bit 1400 to the PDCs 1412.
In an embodiment, the plurality of PDCs 1412 may be secured to the
blades 1404 using a brazing technique, a mechanical fastener, a
high temperature adhesive, press-fitting, or another suitable
technique. The rotary drill bit 1400 may then be used in one or
more subterranean drilling operations until at least one of the
plurality of PDCs 1412 spall ("spalled PDC"). Spalling of the PDCs
1412 may be detected by sudden changes in force exerted by the
plurality of PDCs 1412 against a subterranean surface, visual
inspection, audible cues, or combinations thereof, etc. After one
or more PDCS 1412 spall, the spalled PDC 1412 may be removed from
the rotary drill bit 1400. For example, if the spalled PDC 1412 is
brazed to the rotary drill bit 1400, the spalled PDC 1412 may be
heated sufficiently to melt at least some of the braze material.
The spalled PDC 1412 may then be rotated relative to the rotary
drill bit 1400 to position a portion of the spalled PDC 1412 that
does not include a spalled region in a cutting position. The
spalled PDC 1412 may then be secured to the rotary drill bit 1400
using any of the techniques previously disclosed. The rotary drill
bit 1400 may then be used in subterranean drilling operations.
FIGS. 14A and 14B merely depict one embodiment of a rotary drill
bit that employs at least one PDC fabricated and structured in
accordance with the disclosed embodiments, without limitation. The
rotary drill bit 1400 is used to represent any number of
earth-boring tools or drilling tools, including, for example, core
bits, roller-cone bits, fixed-cutter bits, eccentric bits,
bi-center bits, reamers, reamer wings, or any other downhole tool
including superabrasive compacts, without limitation.
The PDCs disclosed herein may also be utilized in applications
other than cutting technology. For example, the disclosed PDC
embodiments may be used in wire dies, bearings, artificial joints,
inserts, cutting elements, and heat sinks. Thus, any of the PDCs
disclosed herein may be employed in an article of manufacture
including at least one superabrasive element or compact.
Thus, the embodiments of PDCs disclosed herein may be used in any
apparatus or structure in which at least one conventional PDC is
typically used. In one embodiment, a rotor and a stator, assembled
to form a thrust-bearing apparatus, may each include one or more
PDCs (e.g., PDC 100 of FIGS. 1A and 1B) configured according to any
of the embodiments disclosed herein and may be operably assembled
to a downhole drilling assembly. U.S. Pat. Nos. 4,410,054;
4,560,014; 5,364,192; 5,368,398; and 5,480,233, the disclosure of
each of which is incorporated herein, in its entirety, by this
reference, disclose subterranean drilling systems within which
bearing apparatuses utilizing PDCs disclosed herein may be
incorporated. The embodiments of PDCs disclosed herein may also
form all or part of heat sinks, wire dies, bearing elements,
cutting elements, cutting inserts (e.g., on a roller-cone-type
drill bit), machining inserts, or any other article of manufacture
as known in the art. Other examples of articles of manufacture that
may use any of the PDCs disclosed herein are disclosed in U.S. Pat.
Nos. 4,811,801; 4,274,900; 4,268,276; 4,468,138; 4,738,322;
4,913,247; 5,016,718; 5,092,687; 5,120,327; 5,135,061; 5,154,245;
5,460,233; 5,544,713; and 6,793,681, the disclosure of each of
which is incorporated herein, in its entirety, by this reference.
Examples of other articles of manufactures that the PDCs disclosed
herein can be used in are disclosed in U.S. Provisional Patent
Application No. 62/232,732; U.S. patent application Ser. Nos.
13/790,046, 14/273,360, 14/275,574, and 14/811,699.
While various aspects and embodiments have been disclosed herein,
other aspects and embodiments are contemplated. The various aspects
and embodiment disclosed herein are for purposes of illustration
and are not intended to be limiting. Additionally, the words
"including," having," and variants thereof (e.g., "includes" and
"has") as used herein, including the claims, shall be open ended
and have the same meaning as the word "comprising" and variants
thereof (e.g., "comprise" and "comprises").
* * * * *